From 21a13652df728c9571f899caf4949d5d46f49db7 Mon Sep 17 00:00:00 2001
From: johannst <johannst@users.noreply.github.com>
Date: Wed, 1 May 2024 17:39:45 +0000
Subject: deploy: 7ca41565c4e70b212cb88a4d18c18fa35768df6d

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@@ -89,7 +89,7 @@
 
         <nav id="sidebar" class="sidebar" aria-label="Table of contents">
             <div class="sidebar-scrollbox">
-                <ol class="chapter"><li class="chapter-item expanded affix "><a href="intro.html">Introduction</a></li><li class="chapter-item expanded "><a href="tools/index.html"><strong aria-hidden="true">1.</strong> Tools</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="tools/zsh.html"><strong aria-hidden="true">1.1.</strong> zsh</a></li><li class="chapter-item expanded "><a href="tools/bash.html"><strong aria-hidden="true">1.2.</strong> bash</a></li><li class="chapter-item expanded "><a href="tools/fish.html"><strong aria-hidden="true">1.3.</strong> fish</a></li><li class="chapter-item expanded "><a href="tools/tmux.html"><strong aria-hidden="true">1.4.</strong> tmux</a></li><li class="chapter-item expanded "><a href="tools/git.html"><strong aria-hidden="true">1.5.</strong> git</a></li><li class="chapter-item expanded "><a href="tools/awk.html"><strong aria-hidden="true">1.6.</strong> awk</a></li><li class="chapter-item expanded "><a href="tools/emacs.html"><strong aria-hidden="true">1.7.</strong> emacs</a></li><li class="chapter-item expanded "><a href="tools/gpg.html"><strong aria-hidden="true">1.8.</strong> gpg</a></li><li class="chapter-item expanded "><a href="tools/gdb.html"><strong aria-hidden="true">1.9.</strong> gdb</a></li><li class="chapter-item expanded "><a href="tools/gdbserver.html"><strong aria-hidden="true">1.10.</strong> gdbserver</a></li><li class="chapter-item expanded "><a href="tools/radare2.html"><strong aria-hidden="true">1.11.</strong> radare2</a></li><li class="chapter-item expanded "><a href="tools/qemu.html"><strong aria-hidden="true">1.12.</strong> qemu</a></li><li class="chapter-item expanded "><a href="tools/pacman.html"><strong aria-hidden="true">1.13.</strong> pacman</a></li><li class="chapter-item expanded "><a href="tools/dot.html"><strong aria-hidden="true">1.14.</strong> dot</a></li><li class="chapter-item expanded "><a href="tools/ffmpeg.html"><strong aria-hidden="true">1.15.</strong> ffmpeg</a></li><li class="chapter-item expanded "><a href="tools/column.html"><strong aria-hidden="true">1.16.</strong> column</a></li><li class="chapter-item expanded "><a href="tools/sort.html"><strong aria-hidden="true">1.17.</strong> sort</a></li><li class="chapter-item expanded "><a href="tools/sed.html"><strong aria-hidden="true">1.18.</strong> sed</a></li><li class="chapter-item expanded "><a href="tools/gnuplot.html"><strong aria-hidden="true">1.19.</strong> gnuplot</a></li></ol></li><li class="chapter-item expanded "><a href="monitor/index.html"><strong aria-hidden="true">2.</strong> Resource analysis & monitor</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="monitor/lsof.html"><strong aria-hidden="true">2.1.</strong> lsof</a></li><li class="chapter-item expanded "><a href="monitor/ss.html"><strong aria-hidden="true">2.2.</strong> ss</a></li><li class="chapter-item expanded "><a href="monitor/pidstat.html"><strong aria-hidden="true">2.3.</strong> pidstat</a></li><li class="chapter-item expanded "><a href="monitor/pgrep.html"><strong aria-hidden="true">2.4.</strong> pgrep</a></li><li class="chapter-item expanded "><a href="monitor/ps.html"><strong aria-hidden="true">2.5.</strong> ps</a></li><li class="chapter-item expanded "><a href="monitor/pmap.html"><strong aria-hidden="true">2.6.</strong> pmap</a></li><li class="chapter-item expanded "><a href="monitor/pstack.html"><strong aria-hidden="true">2.7.</strong> pstack</a></li></ol></li><li class="chapter-item expanded "><a href="trace_profile/index.html"><strong aria-hidden="true">3.</strong> Trace and Profile</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="trace_profile/time.html"><strong aria-hidden="true">3.1.</strong> time</a></li><li class="chapter-item expanded "><a href="trace_profile/strace.html"><strong aria-hidden="true">3.2.</strong> strace</a></li><li class="chapter-item expanded "><a href="trace_profile/ltrace.html"><strong aria-hidden="true">3.3.</strong> ltrace</a></li><li class="chapter-item expanded "><a href="trace_profile/perf.html"><strong aria-hidden="true">3.4.</strong> perf</a></li><li class="chapter-item expanded "><a href="trace_profile/oprofile.html"><strong aria-hidden="true">3.5.</strong> OProfile</a></li><li class="chapter-item expanded "><a href="trace_profile/callgrind.html"><strong aria-hidden="true">3.6.</strong> callgrind</a></li></ol></li><li class="chapter-item expanded "><a href="binary/index.html"><strong aria-hidden="true">4.</strong> Binary</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="binary/od.html"><strong aria-hidden="true">4.1.</strong> od</a></li><li class="chapter-item expanded "><a href="binary/xxd.html"><strong aria-hidden="true">4.2.</strong> xxd</a></li><li class="chapter-item expanded "><a href="binary/readelf.html"><strong aria-hidden="true">4.3.</strong> readelf</a></li><li class="chapter-item expanded "><a href="binary/objdump.html"><strong aria-hidden="true">4.4.</strong> objdump</a></li><li class="chapter-item expanded "><a href="binary/nm.html"><strong aria-hidden="true">4.5.</strong> nm</a></li></ol></li><li class="chapter-item expanded "><a href="development/index.html"><strong aria-hidden="true">5.</strong> Development</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="development/c++filt.html"><strong aria-hidden="true">5.1.</strong> c++filt</a></li><li class="chapter-item expanded "><a href="development/c++.html"><strong aria-hidden="true">5.2.</strong> c++</a></li><li class="chapter-item expanded "><a href="development/glibc.html"><strong aria-hidden="true">5.3.</strong> glibc</a></li><li class="chapter-item expanded "><a href="development/gcc.html"><strong aria-hidden="true">5.4.</strong> gcc</a></li><li class="chapter-item expanded "><a href="development/cmake.html"><strong aria-hidden="true">5.5.</strong> cmake</a></li><li class="chapter-item expanded "><a href="development/make.html"><strong aria-hidden="true">5.6.</strong> make</a></li><li class="chapter-item expanded "><a href="development/ld.so.html"><strong aria-hidden="true">5.7.</strong> ld.so</a></li><li class="chapter-item expanded "><a href="development/symbolver.html"><strong aria-hidden="true">5.8.</strong> symbol versioning</a></li><li class="chapter-item expanded "><a href="development/python.html"><strong aria-hidden="true">5.9.</strong> python</a></li><li class="chapter-item expanded "><a href="development/gcov.html"><strong aria-hidden="true">5.10.</strong> gcov</a></li><li class="chapter-item expanded "><a href="development/pgo.html"><strong aria-hidden="true">5.11.</strong> pgo</a></li></ol></li><li class="chapter-item expanded "><a href="linux/index.html"><strong aria-hidden="true">6.</strong> Linux</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="linux/systemd.html"><strong aria-hidden="true">6.1.</strong> systemd</a></li><li class="chapter-item expanded "><a href="linux/coredump.html"><strong aria-hidden="true">6.2.</strong> coredump</a></li><li class="chapter-item expanded "><a href="linux/ptrace_scope.html"><strong aria-hidden="true">6.3.</strong> ptrace_scope</a></li><li class="chapter-item expanded "><a href="linux/cryptsetup.html"><strong aria-hidden="true">6.4.</strong> cryptsetup</a></li><li class="chapter-item expanded "><a href="linux/swap.html"><strong aria-hidden="true">6.5.</strong> swap</a></li><li class="chapter-item expanded "><a href="linux/input.html"><strong aria-hidden="true">6.6.</strong> input</a></li><li class="chapter-item expanded "><a href="linux/acl.html"><strong aria-hidden="true">6.7.</strong> acl</a></li><li class="chapter-item expanded "><a href="linux/zfs.html"><strong aria-hidden="true">6.8.</strong> zfs</a></li></ol></li><li class="chapter-item expanded "><a href="network/index.html"><strong aria-hidden="true">7.</strong> Network</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="network/tcpdump.html"><strong aria-hidden="true">7.1.</strong> tcpdump</a></li><li class="chapter-item expanded "><a href="network/tshark.html"><strong aria-hidden="true">7.2.</strong> tshark</a></li><li class="chapter-item expanded "><a href="network/firewall-cmd.html"><strong aria-hidden="true">7.3.</strong> firewall-cmd</a></li><li class="chapter-item expanded "><a href="network/nftables.html"><strong aria-hidden="true">7.4.</strong> nftables</a></li></ol></li><li class="chapter-item expanded "><a href="web/index.html"><strong aria-hidden="true">8.</strong> Web</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="web/html.html"><strong aria-hidden="true">8.1.</strong> html</a></li><li class="chapter-item expanded "><a href="web/css.html"><strong aria-hidden="true">8.2.</strong> css</a></li><li class="chapter-item expanded "><a href="web/chartjs.html"><strong aria-hidden="true">8.3.</strong> chartjs</a></li></ol></li><li class="chapter-item expanded "><a href="arch/index.html"><strong aria-hidden="true">9.</strong> Arch</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="arch/x86_64.html"><strong aria-hidden="true">9.1.</strong> x86_64</a></li><li class="chapter-item expanded "><a href="arch/arm64.html"><strong aria-hidden="true">9.2.</strong> arm64</a></li><li class="chapter-item expanded "><a href="arch/armv7.html"><strong aria-hidden="true">9.3.</strong> armv7</a></li><li class="chapter-item expanded "><a href="arch/riscv.html"><strong aria-hidden="true">9.4.</strong> riscv</a></li></ol></li></ol>
+                <ol class="chapter"><li class="chapter-item expanded affix "><a href="intro.html">Introduction</a></li><li class="chapter-item expanded "><a href="shells/index.html"><strong aria-hidden="true">1.</strong> Shells</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="shells/zsh.html"><strong aria-hidden="true">1.1.</strong> zsh</a></li><li class="chapter-item expanded "><a href="shells/bash.html"><strong aria-hidden="true">1.2.</strong> bash</a></li><li class="chapter-item expanded "><a href="shells/fish.html"><strong aria-hidden="true">1.3.</strong> fish</a></li></ol></li><li class="chapter-item expanded "><a href="cli/index.html"><strong aria-hidden="true">2.</strong> CLI foo</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="cli/awk.html"><strong aria-hidden="true">2.1.</strong> awk</a></li><li class="chapter-item expanded "><a href="cli/sed.html"><strong aria-hidden="true">2.2.</strong> sed</a></li><li class="chapter-item expanded "><a href="cli/column.html"><strong aria-hidden="true">2.3.</strong> column</a></li><li class="chapter-item expanded "><a href="cli/sort.html"><strong aria-hidden="true">2.4.</strong> sort</a></li><li class="chapter-item expanded "><a href="cli/tr.html"><strong aria-hidden="true">2.5.</strong> tr</a></li></ol></li><li class="chapter-item expanded "><a href="tools/index.html"><strong aria-hidden="true">3.</strong> Tools</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="tools/tmux.html"><strong aria-hidden="true">3.1.</strong> tmux</a></li><li class="chapter-item expanded "><a href="tools/emacs.html"><strong aria-hidden="true">3.2.</strong> emacs</a></li><li class="chapter-item expanded "><a href="tools/gpg.html"><strong aria-hidden="true">3.3.</strong> gpg</a></li><li class="chapter-item expanded "><a href="tools/radare2.html"><strong aria-hidden="true">3.4.</strong> radare2</a></li><li class="chapter-item expanded "><a href="tools/qemu.html"><strong aria-hidden="true">3.5.</strong> qemu</a></li><li class="chapter-item expanded "><a href="tools/pacman.html"><strong aria-hidden="true">3.6.</strong> pacman</a></li><li class="chapter-item expanded "><a href="tools/dot.html"><strong aria-hidden="true">3.7.</strong> dot</a></li><li class="chapter-item expanded "><a href="tools/ffmpeg.html"><strong aria-hidden="true">3.8.</strong> ffmpeg</a></li><li class="chapter-item expanded "><a href="tools/gnuplot.html"><strong aria-hidden="true">3.9.</strong> gnuplot</a></li><li class="chapter-item expanded "><a href="tools/restic.html"><strong aria-hidden="true">3.10.</strong> restic</a></li></ol></li><li class="chapter-item expanded "><a href="monitor/index.html"><strong aria-hidden="true">4.</strong> Resource analysis & monitor</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="monitor/lsof.html"><strong aria-hidden="true">4.1.</strong> lsof</a></li><li class="chapter-item expanded "><a href="monitor/pidstat.html"><strong aria-hidden="true">4.2.</strong> pidstat</a></li><li class="chapter-item expanded "><a href="monitor/pgrep.html"><strong aria-hidden="true">4.3.</strong> pgrep</a></li><li class="chapter-item expanded "><a href="monitor/ps.html"><strong aria-hidden="true">4.4.</strong> ps</a></li><li class="chapter-item expanded "><a href="monitor/pmap.html"><strong aria-hidden="true">4.5.</strong> pmap</a></li><li class="chapter-item expanded "><a href="monitor/pstack.html"><strong aria-hidden="true">4.6.</strong> pstack</a></li></ol></li><li class="chapter-item expanded "><a href="trace_profile/index.html"><strong aria-hidden="true">5.</strong> Trace and Profile</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="trace_profile/time.html"><strong aria-hidden="true">5.1.</strong> time</a></li><li class="chapter-item expanded "><a href="trace_profile/strace.html"><strong aria-hidden="true">5.2.</strong> strace</a></li><li class="chapter-item expanded "><a href="trace_profile/ltrace.html"><strong aria-hidden="true">5.3.</strong> ltrace</a></li><li class="chapter-item expanded "><a href="trace_profile/perf.html"><strong aria-hidden="true">5.4.</strong> perf</a></li><li class="chapter-item expanded "><a href="trace_profile/oprofile.html"><strong aria-hidden="true">5.5.</strong> OProfile</a></li><li class="chapter-item expanded "><a href="trace_profile/callgrind.html"><strong aria-hidden="true">5.6.</strong> callgrind</a></li></ol></li><li class="chapter-item expanded "><a href="debug/index.html"><strong aria-hidden="true">6.</strong> Debug</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="debug/gdb.html"><strong aria-hidden="true">6.1.</strong> gdb</a></li><li class="chapter-item expanded "><a href="debug/gdbserver.html"><strong aria-hidden="true">6.2.</strong> gdbserver</a></li></ol></li><li class="chapter-item expanded "><a href="binary/index.html"><strong aria-hidden="true">7.</strong> Binary</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="binary/od.html"><strong aria-hidden="true">7.1.</strong> od</a></li><li class="chapter-item expanded "><a href="binary/xxd.html"><strong aria-hidden="true">7.2.</strong> xxd</a></li><li class="chapter-item expanded "><a href="binary/readelf.html"><strong aria-hidden="true">7.3.</strong> readelf</a></li><li class="chapter-item expanded "><a href="binary/objdump.html"><strong aria-hidden="true">7.4.</strong> objdump</a></li><li class="chapter-item expanded "><a href="binary/nm.html"><strong aria-hidden="true">7.5.</strong> nm</a></li></ol></li><li class="chapter-item expanded "><a href="development/index.html"><strong aria-hidden="true">8.</strong> Development</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="development/c++filt.html"><strong aria-hidden="true">8.1.</strong> c++filt</a></li><li class="chapter-item expanded "><a href="development/c++.html"><strong aria-hidden="true">8.2.</strong> c++</a></li><li class="chapter-item expanded "><a href="development/glibc.html"><strong aria-hidden="true">8.3.</strong> glibc</a></li><li class="chapter-item expanded "><a href="development/gcc.html"><strong aria-hidden="true">8.4.</strong> gcc</a></li><li class="chapter-item expanded "><a href="development/git.html"><strong aria-hidden="true">8.5.</strong> git</a></li><li class="chapter-item expanded "><a href="development/cmake.html"><strong aria-hidden="true">8.6.</strong> cmake</a></li><li class="chapter-item expanded "><a href="development/make.html"><strong aria-hidden="true">8.7.</strong> make</a></li><li class="chapter-item expanded "><a href="development/ld.so.html"><strong aria-hidden="true">8.8.</strong> ld.so</a></li><li class="chapter-item expanded "><a href="development/symbolver.html"><strong aria-hidden="true">8.9.</strong> symbol versioning</a></li><li class="chapter-item expanded "><a href="development/python.html"><strong aria-hidden="true">8.10.</strong> python</a></li><li class="chapter-item expanded "><a href="development/gcov.html"><strong aria-hidden="true">8.11.</strong> gcov</a></li><li class="chapter-item expanded "><a href="development/pgo.html"><strong aria-hidden="true">8.12.</strong> pgo</a></li></ol></li><li class="chapter-item expanded "><a href="linux/index.html"><strong aria-hidden="true">9.</strong> Linux</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="linux/systemd.html"><strong aria-hidden="true">9.1.</strong> systemd</a></li><li class="chapter-item expanded "><a href="linux/coredump.html"><strong aria-hidden="true">9.2.</strong> coredump</a></li><li class="chapter-item expanded "><a href="linux/ptrace_scope.html"><strong aria-hidden="true">9.3.</strong> ptrace_scope</a></li><li class="chapter-item expanded "><a href="linux/cryptsetup.html"><strong aria-hidden="true">9.4.</strong> cryptsetup</a></li><li class="chapter-item expanded "><a href="linux/swap.html"><strong aria-hidden="true">9.5.</strong> swap</a></li><li class="chapter-item expanded "><a href="linux/input.html"><strong aria-hidden="true">9.6.</strong> input</a></li><li class="chapter-item expanded "><a href="linux/acl.html"><strong aria-hidden="true">9.7.</strong> acl</a></li><li class="chapter-item expanded "><a href="linux/zfs.html"><strong aria-hidden="true">9.8.</strong> zfs</a></li></ol></li><li class="chapter-item expanded "><a href="network/index.html"><strong aria-hidden="true">10.</strong> Network</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="network/ss.html"><strong aria-hidden="true">10.1.</strong> ss</a></li><li class="chapter-item expanded "><a href="network/tcpdump.html"><strong aria-hidden="true">10.2.</strong> tcpdump</a></li><li class="chapter-item expanded "><a href="network/tshark.html"><strong aria-hidden="true">10.3.</strong> tshark</a></li><li class="chapter-item expanded "><a href="network/firewall-cmd.html"><strong aria-hidden="true">10.4.</strong> firewall-cmd</a></li><li class="chapter-item expanded "><a href="network/nftables.html"><strong aria-hidden="true">10.5.</strong> nftables</a></li></ol></li><li class="chapter-item expanded "><a href="web/index.html"><strong aria-hidden="true">11.</strong> Web</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="web/html.html"><strong aria-hidden="true">11.1.</strong> html</a></li><li class="chapter-item expanded "><a href="web/css.html"><strong aria-hidden="true">11.2.</strong> css</a></li><li class="chapter-item expanded "><a href="web/chartjs.html"><strong aria-hidden="true">11.3.</strong> chartjs</a></li></ol></li><li class="chapter-item expanded "><a href="arch/index.html"><strong aria-hidden="true">12.</strong> Arch</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="arch/x86_64.html"><strong aria-hidden="true">12.1.</strong> x86_64</a></li><li class="chapter-item expanded "><a href="arch/armv8.html"><strong aria-hidden="true">12.2.</strong> armv8</a></li><li class="chapter-item expanded "><a href="arch/arm64.html"><strong aria-hidden="true">12.3.</strong> arm64</a></li><li class="chapter-item expanded "><a href="arch/armv7.html"><strong aria-hidden="true">12.4.</strong> armv7</a></li><li class="chapter-item expanded "><a href="arch/riscv.html"><strong aria-hidden="true">12.5.</strong> riscv</a></li></ol></li></ol>
             </div>
             <div id="sidebar-resize-handle" class="sidebar-resize-handle">
                 <div class="sidebar-resize-indicator"></div>
@@ -180,27 +180,11 @@
                         <h1 id="notes"><a class="header" href="#notes">Notes</a></h1>
 <p>A personal collection of notes and cheatsheets.</p>
 <p>Source code is located at <a href="https://github.com/johannst/notes">johannst/notes</a>.</p>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="tools"><a class="header" href="#tools">Tools</a></h1>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="shells"><a class="header" href="#shells">Shells</a></h1>
 <ul>
-<li><a href="tools/./zsh.html">zsh</a></li>
-<li><a href="tools/./bash.html">bash</a></li>
-<li><a href="tools/./fish.html">fish</a></li>
-<li><a href="tools/./tmux.html">tmux</a></li>
-<li><a href="tools/./git.html">git</a></li>
-<li><a href="tools/./awk.html">awk</a></li>
-<li><a href="tools/./emacs.html">emacs</a></li>
-<li><a href="tools/./gpg.html">gpg</a></li>
-<li><a href="tools/./gdb.html">gdb</a></li>
-<li><a href="tools/./gdbserver.html">gdbserver</a></li>
-<li><a href="tools/./radare2.html">radare2</a></li>
-<li><a href="tools/./qemu.html">qemu</a></li>
-<li><a href="tools/./pacman.html">pacman</a></li>
-<li><a href="tools/./dot.html">dot</a></li>
-<li><a href="tools/./ffmpeg.html">ffmpeg</a></li>
-<li><a href="tools/./column.html">column</a></li>
-<li><a href="tools/./sort.html">sort</a></li>
-<li><a href="tools/./sed.html">sed</a></li>
-<li><a href="tools/./gnuplot.html">gnuplot</a></li>
+<li><a href="shells/./zsh.html">zsh</a></li>
+<li><a href="shells/./bash.html">bash</a></li>
+<li><a href="shells/./fish.html">fish</a></li>
 </ul>
 <div style="break-before: page; page-break-before: always;"></div><h1 id="zsh1"><a class="header" href="#zsh1">zsh(1)</a></h1>
 <h2 id="keybindings"><a class="header" href="#keybindings">Keybindings</a></h2>
@@ -337,7 +321,7 @@ echo ${(kv)vec}       # a aa b bb
 for k v in ${(kv)vec)}; do ...; done
 </code></pre>
 <h2 id="io-redirections"><a class="header" href="#io-redirections">I/O redirections</a></h2>
-<p>See <a href="tools/bash.html#io-redirection">bash - I/O redirection</a></p>
+<p>See <a href="shells/bash.html#io-redirection">bash - I/O redirection</a></p>
 <h2 id="process-substitution"><a class="header" href="#process-substitution">Process substitution</a></h2>
 <p>Process substitution allows to redirect the stdout of multiple processes at
 once.</p>
@@ -548,7 +532,7 @@ NAME=VAR2
 printf -v "$NAME" "%s" "def"
 </code></pre>
 <blockquote>
-<p>Note: <code>prefix</code>/<code>suffix</code>/<code>pattern</code> are expanded as <a href="tools/bash.html#pathname">pathnames</a>.</p>
+<p>Note: <code>prefix</code>/<code>suffix</code>/<code>pattern</code> are expanded as <a href="shells/bash.html#pathname">pathnames</a>.</p>
 </blockquote>
 <h3 id="pathname"><a class="header" href="#pathname">Pathname</a></h3>
 <pre><code class="language-bash">*           match any string
@@ -970,475 +954,454 @@ status -f              # abs path of current file
   breakpoint ................ halt script execution and gives shell (C-d | exit
                               to continue)
 </code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="tmux1"><a class="header" href="#tmux1">tmux(1)</a></h1>
-<p>Terminology:</p>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="cli-foo"><a class="header" href="#cli-foo">CLI foo</a></h1>
 <ul>
-<li><code>session</code> is a collection of pseudo terminals which can have multiple
-<code>windows</code></li>
-<li><code>window</code> uses the entire screen and can be split into rectangular <code>panes</code></li>
-<li><code>pane</code> is a single pseudo terminal instance</li>
+<li><a href="cli/./awk.html">awk</a></li>
+<li><a href="cli/./sed.html">sed</a></li>
+<li><a href="cli/./column.html">column</a></li>
+<li><a href="cli/./sort.html">sort</a></li>
+<li><a href="cli/./tr.html">tr</a></li>
 </ul>
-<h1 id="tmux-cli"><a class="header" href="#tmux-cli">Tmux cli</a></h1>
-<pre><code class="language-markdown"># Session
-tmux                        creates new session
-tmux ls                     list running sessions
-tmux kill-session -t &lt;s&gt;    kill running session &lt;s&gt;
-tmux attach -t &lt;s&gt; [-d]     attach to session &lt;s&gt;, detach other clients [-d]
-tmux detach -s &lt;s&gt;          detach all clients from session &lt;s&gt;
-
-# Environment
-tmux showenv -g             show global tmux environment variables
-tmux setenv -g &lt;var&gt; &lt;val&gt;  set variable in global tmux env
-
-# Misc
-tmux source-file &lt;file&gt;     source config &lt;file&gt;
-tmux lscm                   list available tmux commnds
-tmux show -g                show global tmux options
-tmux display &lt;msg&gt;          display message in tmux status line
-</code></pre>
-<h2 id="scripting"><a class="header" href="#scripting">Scripting</a></h2>
-<pre><code class="language-markdown"># Session
-tmux list-sessions -F '#S'           list running sessions, only IDs
-
-# Window
-tmux list-windows -F '#I' -t &lt;s&gt;     list window IDs for session &lt;s&gt;
-tmux selectw -t &lt;s&gt;:&lt;w&gt;              select window &lt;w&gt; in session &lt;s&gt;
-
-# Pane
-tmux list-panes -F '#P' -t &lt;s&gt;:&lt;w&gt;   list pane IDs for window &lt;w&gt; in session &lt;s&gt;
-tmux selectp -t &lt;s&gt;:&lt;w&gt;.&lt;p&gt;          select pane &lt;p&gt; in window &lt;w&gt; in session &lt;s&gt;
-
-# Run commands
-tmux send -t &lt;s&gt;:&lt;w&gt;.&lt;p&gt; "ls" C-m    send cmds/keys to pane
-tmux run -t &lt;p&gt; &lt;sh-cmd&gt;             run shell command &lt;sh-cmd&gt; in background and report output on pane -t &lt;p&gt;
+<div style="break-before: page; page-break-before: always;"></div><h1 id="awk1"><a class="header" href="#awk1">awk(1)</a></h1>
+<pre><code class="language-markdown">awk [opt] program [input]
+    -F &lt;sepstr&gt;        field separator string (can be regex)
+    program            awk program
+    input              file or stdin if not file given
 </code></pre>
-<p>For example cycle through all panes in all windows in all sessions:</p>
-<pre><code class="language-bash"># bash
-for s in $(tmux list-sessions -F '#S'); do
-    for w in $(tmux list-windows -F '#I' -t $s); do
-        for p in $(tmux list-panes -F '#P' -t $s:$w); do
-            echo $s:$w.$p
-        done
-    done
-done
+<h2 id="input-processing"><a class="header" href="#input-processing">Input processing</a></h2>
+<p>Input is processed in two stages:</p>
+<ol>
+<li>Splitting input into a sequence of <code>records</code>.
+By default split at <code>newline</code> character, but can be changed via the
+builtin <code>RS</code> variable.</li>
+<li>Splitting a <code>record</code> into <code>fields</code>. By default strings without <code>whitespace</code>,
+but can be changed via the builtin variable <code>FS</code> or command line option
+<code>-F</code>.</li>
+</ol>
+<p>Fields are accessed as follows:</p>
+<ul>
+<li><code>$0</code> whole <code>record</code></li>
+<li><code>$1</code> field one</li>
+<li><code>$2</code> field two</li>
+<li>...</li>
+</ul>
+<h2 id="program"><a class="header" href="#program">Program</a></h2>
+<p>An <code>awk</code> program is composed of pairs of the form:</p>
+<pre><code class="language-markdown">pattern { action }
 </code></pre>
-<h1 id="bindings"><a class="header" href="#bindings">Bindings</a></h1>
-<pre><code class="language-markdown">prefix d    detach from current session
-prefix c    create new window
-prefix w    open window list
-prefix $    rename session
-prefix ,    rename window
-prefix .    move current window
+<p>The program is run against each <code>record</code> in the input stream. If a <code>pattern</code>
+matches a <code>record</code> the corresponding <code>action</code> is executed and can access the
+<code>fields</code>.</p>
+<pre><code class="language-markdown">INPUT
+  |
+  v
+record ----&gt; ∀ pattern matched
+  |                   |
+  v                   v
+fields ----&gt; run associated action
 </code></pre>
-<p>Following bindings are specific to my <a href="https://github.com/johannst/dotfiles/blob/master/tmux.conf"><code>tmux.conf</code></a>:</p>
-<pre><code class="language-markdown">C-s         prefix
-
-# Panes
-prefix s    horizontal split
-prefix v    vertical split
-prefix f    toggle maximize/minimize current pane
-
-# Movement
-prefix Tab  toggle between window
-
-prefix h    move to pane left
-prefix j    move to pane down
-prefix k    move to pane up
-prefix l    move to pane right
-
-# Resize
-prefix C-h  resize pane left
-prefix C-j  resize pane down
-prefix C-k  resize pane up
-prefix C-l  resize pane right
-
-# Copy/Paste
-prefix C-v    enter copy mode
-prefix C-p    paste yanked text
-prefix C-b    open copy-buffer list
-
-# In Copy Mode
-v     enable visual mode
-y     yank selected text
+<p>Any valid awk <code>expr</code> can be a <code>pattern</code>.</p>
+<p>An example is the regex pattern <code>/abc/ { print $1 }</code> which prints the first
+field if the record matches the regex <code>/abc/</code>. This form is actually a short
+version for <code>$0 ~ /abc/ { print $1 }</code>, see the regex comparison operator
+below.</p>
+<h3 id="special-pattern"><a class="header" href="#special-pattern">Special pattern</a></h3>
+<p>awk provides two special patterns, <code>BEGIN</code> and <code>END</code>, which can be used
+multiple times. Actions with those patterns are <strong>executed exactly once</strong>.</p>
+<ul>
+<li><code>BEGIN</code> actions are run before processing the first record</li>
+<li><code>END</code> actions are run after processing the last record</li>
+</ul>
+<h3 id="special-variables"><a class="header" href="#special-variables">Special variables</a></h3>
+<ul>
+<li><code>RS</code> <em>record separator</em>: first char is the record separator, by default
+<newline></li>
+<li><code>FS</code> <em>field separator</em>: regex to split records into fields, by default
+<space></li>
+<li><code>NR</code> <em>number record</em>: number of current record</li>
+<li><code>NF</code> <em>number fields</em>: number of fields in the current record</li>
+</ul>
+<h3 id="special-statements--functions"><a class="header" href="#special-statements--functions">Special statements &amp; functions</a></h3>
+<ul>
+<li>
+<p><code>printf "fmt", args...</code></p>
+<p>Print format string, args are comma separated.</p>
+<ul>
+<li><code>%s</code> string</li>
+<li><code>%d</code> decimal</li>
+<li><code>%x</code> hex</li>
+<li><code>%f</code> float</li>
+</ul>
+<p>Width can be specified as <code>%Ns</code>, this reserves <code>N</code> chars for a string.
+For floats one can use <code>%N.Mf</code>, <code>N</code> is the total number including <code>.</code> and
+<code>M</code>.</p>
+</li>
+<li>
+<p><code>sprintf("fmt", expr, ...)</code></p>
+<p>Format the expressions according to the format string. Similar as <code>printf</code>,
+but this is a function and return value can be assigned to a variable.</p>
+</li>
+<li>
+<p><code>strftime("fmt")</code></p>
+<p>Print time stamp formatted by <code>fmt</code>.</p>
+<ul>
+<li><code>%Y</code> full year (eg 2020)</li>
+<li><code>%m</code> month (01-12)</li>
+<li><code>%d</code> day (01-31)</li>
+<li><code>%F</code> alias for <code>%Y-%m-%d</code></li>
+<li><code>%H</code> hour (00-23)</li>
+<li><code>%M</code> minute (00-59)</li>
+<li><code>%S</code> second (00-59)</li>
+<li><code>%T</code> alias for <code>%H:%M:%S</code></li>
+</ul>
+</li>
+<li>
+<p><code>S ~ R</code>, <code>S !~ R</code></p>
+<p>The regex comparison operator, where the former returns true if the string
+<code>S</code> matches the regex <code>R</code>, and the latter is the negated form.
+The regex can be either a
+<a href="https://www.gnu.org/software/gawk/manual/html_node/Regexp-Usage.html">constant</a>
+or <a href="https://www.gnu.org/software/gawk/manual/html_node/Computed-Regexps.html">dynamic</a>
+regex.</p>
+</li>
+</ul>
+<h2 id="examples"><a class="header" href="#examples">Examples</a></h2>
+<h3 id="filter-records"><a class="header" href="#filter-records">Filter records</a></h3>
+<pre><code class="language-bash">awk 'NR%2 == 0 { print $0 }' &lt;file&gt;
 </code></pre>
-<h1 id="command-mode"><a class="header" href="#command-mode">Command mode</a></h1>
-<p>To enter command mode <code>prefix :</code>.</p>
-<p>Some useful commands are:</p>
-<pre><code class="language-markdown">setw synchronize-panes on/off       enables/disables synchronized input to all panes
-list-keys -t vi-copy                list keymaps for vi-copy mode
+<p>The pattern <code>NR%2 == 0</code> matches every second record and the action <code>{ print $0 }</code>
+prints the whole record.</p>
+<h3 id="negative-patterns"><a class="header" href="#negative-patterns">Negative patterns</a></h3>
+<pre><code class="language-bash">awk '!/^#/ { print $1 }' &lt;file&gt;
 </code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="git1"><a class="header" href="#git1">git(1)</a></h1>
-<h2 id="working-areas"><a class="header" href="#working-areas">Working areas</a></h2>
-<pre><code class="language-text">+-------------------+ --- stash -----&gt; +-------+
-| working directory |                  | stash |  // Shelving area.
-+-------------------+ &lt;-- stash pop -- +-------+
-      |       ^
-     add      |
-      |     reset
-      v       |
-+-------------------+
-|   staging area    |
-+-------------------+
-      |
-    commit
-      |
-      v
-+-------------------+
-| local repository  |
-+-------------------+
-      |       ^
-     push     |
-      |     fetch /
-      |      pull
-      v       |
-+-------------------+
-| remote repository |
-+-------------------+
+<p>Matches records not starting with <code>#</code>.</p>
+<h3 id="range-patterns"><a class="header" href="#range-patterns">Range patterns</a></h3>
+<pre><code class="language-bash">echo -e "a\nFOO\nb\nc\nBAR\nd" | \
+    awk '/FOO/,/BAR/ { print }'
 </code></pre>
-<h2 id="config"><a class="header" href="#config">Config</a></h2>
-<pre><code class="language-markdown">  git config --list --show-origin ..... list currently set configs and where
-                                        they are coming from
-  git --edit [--global] ............... open config in editor (local or global)
+<p><code>/FOO/,/BAR/</code> define a range pattern of <code>begin_pattern, end_pattern</code>. When
+<code>begin_pattern</code> is matched the range is <strong>turned on</strong> and when the
+<code>end_pattern</code> is matched the range is <strong>turned off</strong>. This matches every record
+in the range <em>inclusive</em>.</p>
+<p>An <em>exclusive</em> range must be handled explicitly, for example as follows.</p>
+<pre><code class="language-bash">echo -e "a\nFOO\nb\nc\nBAR\nd" | \
+    awk '/FOO/,/BAR/ { if (!($1 ~ "FOO") &amp;&amp; !($1 ~ "BAR")) { print } }'
 </code></pre>
-<h2 id="clean"><a class="header" href="#clean">Clean</a></h2>
-<pre><code class="language-markdown">  git clean -X ......... remove only ignored files (-n for dry run)
-  git clean -f -d -x ... remove untracked &amp; ignored files / folders
-  git clean -e &lt;pat&gt; ... exclude pattern from deletion
+<h3 id="access-last-fields-in-records"><a class="header" href="#access-last-fields-in-records">Access last fields in records</a></h3>
+<pre><code class="language-bash">echo 'a b c d e f' | awk '{ print $NF $(NF-1) }'
 </code></pre>
-<h2 id="staging"><a class="header" href="#staging">Staging</a></h2>
-<pre><code class="language-markdown">  git add -p [&lt;file&gt;] ............ partial staging (interactive)
-</code></pre>
-<h2 id="remote"><a class="header" href="#remote">Remote</a></h2>
-<pre><code class="language-markdown">  git remote -v .................. list remotes verbose (with URLs)
-  git remote show [-n] &lt;remote&gt; .. list info for &lt;remote&gt; (like remote HEAD,
-                                   remote branches, tracking mapping)
+<p>Access last fields with arithmetic on the <code>NF</code> number of fields variable.</p>
+<h3 id="split-on-multiple-tokens"><a class="header" href="#split-on-multiple-tokens">Split on multiple tokens</a></h3>
+<pre><code class="language-bash">echo 'a,b;c:d' | awk -F'[,;:]' '{ printf "1=%s | 4=%s\n", $1, $4 }'
 </code></pre>
-<h2 id="branching"><a class="header" href="#branching">Branching</a></h2>
-<pre><code class="language-markdown">  git branch [-a] ................ list available branches; -a to include
-                                   remote branches
-  git branch -vv ................. list branch &amp; annotate with head sha1 &amp;
-                                   remote tracking branch
-  git branch &lt;bname&gt; ............. create local branch with name &lt;bname&gt;
-  git branch -d &lt;bname&gt; .......... delete local branch with name &lt;bname&gt;
-  git checkout &lt;bname&gt; ........... switch to branch with name &lt;bname&gt;
-  git checkout --track &lt;branch&gt; .. start to locally track a remote branch
-  git branch --unset-upstream .... unset remote tracking branch
-
-  # Remote
+<p>Use regex as field separator.</p>
+<h3 id="capture-in-variables"><a class="header" href="#capture-in-variables">Capture in variables</a></h3>
+<pre><code class="language-bash"># /proc/&lt;pid&gt;/status
+#   Name:    cat
+#   ...
+#   VmRSS:   516 kB
+#   ...
 
-  git push -u origin &lt;rbname&gt; ........ push local branch to origin (or other
-                                       remote), and setup &lt;rbname&gt; as tracking
-                                       branch
-  git push origin --delete &lt;rbname&gt; .. delete branch &lt;rbname&gt; from origin (or
-                                       other remote)
+for f in /proc/*/status; do
+    cat $f | awk '
+             /^VmRSS/ { rss = $2/1024 }
+             /^Name/ { name = $2 }
+             END { printf "%16s %6d MB\n", name, rss }';
+done | sort -k2 -n
 </code></pre>
-<h2 id="update-local-from-remote"><a class="header" href="#update-local-from-remote">Update local from remote</a></h2>
-<pre><code class="language-markdown">  git fetch --prune .................. update all remote references and
-                                       remove delete non-existing ones
-                                       (does not merge into local tracking branch)
-  git pull [--rebase] ................ fetch remote references and merge into
-                                       local tracking branch (fast-forward by default).
-                                       Optionally rebase local tracking branch
-                                       on-top of remote branch (in case local
-                                       branch has additional commits compared to remote branch).
+<p>We capture values from <code>VmRSS</code> and <code>Name</code> into variables and print them at the
+<code>END</code> once processing all records is done.</p>
+<h3 id="capture-in-array"><a class="header" href="#capture-in-array">Capture in array</a></h3>
+<pre><code class="language-bash">echo 'a 10
+b 2
+b 4
+a 1' | awk '{
+    vals[$1] += $2
+    cnts[$1] += 1
+}
+END {
+    for (v in vals)
+        printf "%s %d\n", v, vals[v] / cnts [v]
+}'
 </code></pre>
-<h2 id="tags"><a class="header" href="#tags">Tags</a></h2>
-<pre><code class="language-markdown">  git tag -a &lt;tname&gt; -m "descr" ........ creates an annotated tag (full object
-                                         containing tagger, date, ...)
-  git tag -l ........................... list available tags
-  git checkout tag/&lt;tname&gt; ............. checkout specific tag
-  git checkout tag/&lt;tname&gt; -b &lt;bname&gt; .. checkout specific tag in a new branch
+<p>Capture keys and values from different columns and some up the values.
+At the <code>END</code> we compute the average of each key.</p>
+<h3 id="run-shell-command-and-capture-output"><a class="header" href="#run-shell-command-and-capture-output">Run shell command and capture output</a></h3>
+<pre><code class="language-bash">cat /proc/1/status | awk '
+                     /^Pid/ {
+                        "ps --no-header -o user " $2 | getline user;
+                         print user
+                     }'
+</code></pre>
+<p>We build a <code>ps</code> command line and capture the first line of the processes output
+in the <code>user</code> variable and then print it.</p>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="sed1"><a class="header" href="#sed1">sed(1)</a></h1>
+<pre><code>sed [opts] [script] [file]
+  opts:
+    -i          edit file in place
+    -i.bk       edit file in place and create backup file
+                (with .bk suffix, can be specified differently)
+    --follow-symlinks
+                follow symlinks when editing in place
+    -e SCRIPT   add SCRIPT to commands to be executed
+                (can be specified multiple times)
+    -f FILE     add content of FILE to command to be executed
 
-  # Remote
+    --debug     annotate program execution
+</code></pre>
+<h2 id="examples-1"><a class="header" href="#examples-1">Examples</a></h2>
+<h3 id="delete-lines"><a class="header" href="#delete-lines">Delete lines</a></h3>
+<pre><code class="language-sh"># Delete two lines.
+echo -e 'aa\nbb\ncc\ndd' | sed '1d;3d'
+# bb
+# dd
 
-  git push origin --tags .... push local tags to origin (or other remote)
+# Delete last ($) line.
+echo -e 'aa\nbb\ncc\ndd' | sed '$d'
+# aa
+# bb
+# cc
+
+# Delete range of lines.
+echo -e 'aa\nbb\ncc\ndd' | sed '1,3d'
+# dd
+
+# Delete lines matching pattern.
+echo -e 'aa\nbb\ncc\ndd' | sed '/bb/d'
+# aa
+# cc
+# dd
+
+# Delete lines NOT matching pattern.
+echo -e 'aa\nbb\ncc\ndd' | sed '/bb/!d'
+# bb
 </code></pre>
-<h2 id="merging"><a class="header" href="#merging">Merging</a></h2>
-<pre><code class="language-markdown">  git merge [opt] &lt;commit&gt; .... integrate changes from &lt;commit&gt; since
-    opt:                        current branch and &lt;commit&gt; diverged
-      --squash ................ merge all commits into a single one
-      --no-commit ............. dont generate commit if the merge succeeds
+<h3 id="insert-lines"><a class="header" href="#insert-lines">Insert lines</a></h3>
+<pre><code class="language-sh"># Insert before line.
+echo -e 'aa\nbb' | sed '2iABC'
+# aa
+# ABC
+# bb
 
-  git merge-base &lt;commit&gt; &lt;commit&gt;
-                                get the common ancestor, since both commits diverged
+# Insert after line.
+echo -e 'aa\nbb' | sed '2aABC'
+# aa
+# bb
+# ABC
 
-  git rebase -i &lt;upstream&gt; .... interactively rebase on &lt;upstream&gt;, also supports actions
-                                like squashing, editing, rewording, etc of commits
+# Replace line.
+echo -e 'aa\nbb' | sed '2cABC'
+# aa
+# ABC
 
-  git cherry-pick &lt;commit&gt; .... apply commit on current branch
+# Insert before pattern match.
+echo -e 'aa\nbb' | sed '/bb/i 123'
+# aa
+# 123
+# bb
 </code></pre>
-<h2 id="worktree"><a class="header" href="#worktree">Worktree</a></h2>
-<p>Worktrees allow to maintain multiple working trees in the filesystem linked to
-the same repository (shared .git folder).</p>
-<pre><code class="language-markdown">  git worktree add &lt;path&gt; .............. create a tree at &lt;path&gt; with a new branch
-                                         checked out (bname is basename of &lt;path&gt;)
-  git worktree add &lt;path&gt; &lt;bname&gt; ...... create a tree at &lt;path&gt; from existing &lt;bname&gt;
-  git worktree list .................... list existing work trees
-  git worktree remove &lt;tree&gt; ........... remove work tree
-  git worktree prune ................... remove stale bookkeeping files
+<h3 id="substitute-lines"><a class="header" href="#substitute-lines">Substitute lines</a></h3>
+<pre><code class="language-sh"># Substitute by regex.
+echo -e 'aafooaa\ncc' | sed 's/foo/MOOSE/'
+# aaMOOSEaa
+# cc
 </code></pre>
-<h2 id="log--commit-history"><a class="header" href="#log--commit-history">Log &amp; Commit History</a></h2>
-<pre><code class="language-markdown">  git log --oneline ......... shows log in single line per commit -&gt; alias for
-                              '--pretty=oneline --abbrev-commit'
-  git log --graph ........... text based graph of commit history
-  git log --decorate ........ decorate log with REFs
-
-  git log -p &lt;file&gt; ......... show commit history + diffs for &lt;file&gt;
-  git log --oneline &lt;file&gt; .. show commit history for &lt;file&gt; in compact format
+<h3 id="multiple-scripts"><a class="header" href="#multiple-scripts">Multiple scripts</a></h3>
+<pre><code class="language-sh">echo -e 'foo\nbar' | sed -e 's/foo/FOO/' -e 's/FOO/BAR/'
+# BAR
+# bar
 </code></pre>
-<h2 id="diff--commit-info"><a class="header" href="#diff--commit-info">Diff &amp; Commit Info</a></h2>
-<pre><code class="language-markdown">  git diff &lt;commit&gt;..&lt;commit&gt; [&lt;file&gt;] .... show changes between two arbitrary
-                                            commits. If one &lt;commit&gt; is omitted
-                                            it is if HEAD is specified.
-  git diff --name-only &lt;commit&gt;..&lt;commit&gt; . show names of files changed
-  git diff -U$(wc -l &lt;file&gt;) &lt;file&gt; ....... shows complete file with diffs
-                                            instead of usual diff snippets
-  git diff --staged ....................... show diffs of staged files
+<h3 id="edit-inplace-through-symlink"><a class="header" href="#edit-inplace-through-symlink">Edit inplace through symlink</a></h3>
+<pre><code class="language-sh">touch file
+ln -s file link
+ls -l link
+# lrwxrwxrwx 1 johannst johannst 4 Feb  7 23:02 link -&gt; file
 
-  git show --stat &lt;commit&gt; ................ show files changed by &lt;commit&gt;
-  git show &lt;commit&gt; [&lt;file&gt;] .............. show diffs for &lt;commit&gt;
+sed -i --follow-symlinks '1iabc' link
+ls -l link
+# lrwxrwxrwx 1 johannst johannst 4 Feb  7 23:02 link -&gt; file
 
-  git show &lt;commit&gt;:&lt;file&gt; ................ show &lt;file&gt; at &lt;commit&gt;
+sed -i '1iabc' link
+ls -l link
+# -rw-r--r-- 1 johannst johannst 0 Feb  7 23:02 link
 </code></pre>
-<h2 id="patching"><a class="header" href="#patching">Patching</a></h2>
-<pre><code class="language-markdown">  git format-patch &lt;opt&gt; &lt;since&gt;/&lt;revision range&gt;
-    opt:
-      -N ................... use [PATCH] instead [PATCH n/m] in subject when
-                             generating patch description (for patches spanning
-                             multiple commits)
-      --start-number &lt;n&gt; ... start output file generation with &lt;n&gt; as start
-                             number instead '1'
-    since spcifier:
-      -3 .................. e.g: create a patch from last three commits
-      &lt;commit hash&gt; ....... create patch with commits starting after &lt;commit hash&gt;
-
-  git am &lt;patch&gt; ......... apply patch and create a commit for it
+<div style="break-before: page; page-break-before: always;"></div><h1 id="column1"><a class="header" href="#column1">column(1)</a></h1>
+<h2 id="examples-2"><a class="header" href="#examples-2">Examples</a></h2>
+<pre><code class="language-sh"># Show as table (aligned columns), with comma as delimiter from stdin.
+echo -e 'a,b,c\n111,22222,33' | column -t -s ','
 
-  git apply --stat &lt;PATCH&gt; ... see which files the patch would change
-  git apply --check &lt;PATCH&gt; .. see if the patch can be applied cleanly
-  git apply [-3] &lt;PATCH&gt; ..... apply the patch locally without creating a commit,
-                               if the patch does not cleanly apply -3 allows for
-                               a 3-way merge
+# Show file as table.
+column -t -s ',' test.csv
+</code></pre>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="sort1"><a class="header" href="#sort1">sort(1)</a></h1>
+<pre><code>sort [opts] [file]
+  opts:
+    -r      reverse output
+    -b      ignore leading blanks
 
-  # eg: generate patches for each commit from initial commit on
-  git format-patch -N $(git rev-list --max-parents=0 HEAD)
+    -n      sort by numeric
+    -h      sort by human numeric
+    -V      sort by version
 
-  # generate single patch file from a certain commit/ref
-  git format-patch &lt;COMMIT/REF&gt; --stdout &gt; my-patch.patch
+    -k&lt;N&gt;  sort by Nth key
+    -t&lt;S&gt;  field separator
 </code></pre>
-<h2 id="resetting"><a class="header" href="#resetting">Resetting</a></h2>
-<pre><code class="language-markdown">  git reset [opt] &lt;ref|commit&gt;
-    opt:
-      --mixed .................... resets index, but not working tree
-      --hard ..................... matches the working tree and index to that
-                                   of the tree being switched to any changes to
-                                   tracked files in the working tree since
-                                   &lt;commit&gt; are lost
-  git reset HEAD &lt;file&gt; .......... remove file from staging
-  git reset --soft HEAD~1 ........ delete most recent commit but keep work
-  git reset --hard HEAD~1 ........ delete most recent commit and delete work
+<h2 id="examples-3"><a class="header" href="#examples-3">Examples</a></h2>
+<pre><code class="language-sh"># Sort by directory sizes.
+du -sh * | sort -h
 </code></pre>
-<h2 id="submodules"><a class="header" href="#submodules">Submodules</a></h2>
-<pre><code class="language-markdown">  git submodule add &lt;url&gt; [&lt;path&gt;] .......... add new submodule to current project
-  git clone --recursive &lt;url&gt; ............... clone project and recursively all
-                                              submodules (same as using
-                                              'git submodule update --init
-                                              --recursive' after clone)
-  git submodule update --init --recursive ... checkout submodules recursively
-                                              using the commit listed in the
-                                              super-project (in detached HEAD)
-  git submodule update --remote &lt;submod&gt; .... fetch &amp; merge remote changes for
-                                              &lt;submod&gt;, this will pull
-                                              origin/HEAD or a branch specified
-                                              for the submodule
-  git diff --submodule ...................... show commits that are part of the
-                                              submodule diff
+<pre><code class="language-sh"># Sort numeric by second key.
+# The default key separator is non-blank to blank transition.
+echo 'a 4
+d 10
+c 21' | sort -k2 -n
+
+# Sort numeric by second key, split at comma.
+echo 'a,4
+d,10
+c,21' | sort -k2 -n -t,
 </code></pre>
-<h2 id="inspection"><a class="header" href="#inspection">Inspection</a></h2>
-<pre><code class="language-markdown">  git ls-tree [-r] &lt;ref&gt; .... show git tree for &lt;ref&gt;, -r to recursively ls sub-trees
-  git show &lt;obj&gt; ............ show &lt;obj&gt;
-  git cat-file -p &lt;obj&gt; ..... print content of &lt;obj&gt;
+<blockquote>
+<p>Use <code>--debug</code> to annotate part of the line used to sort and hence debug the key usage.</p>
+</blockquote>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="tr1"><a class="header" href="#tr1">tr(1)</a></h1>
+<pre><code>tr [opt] str1 [str2]
+    -d      delete characters in str1
+    -s      squeeze repeating sequence of characters in str1
 </code></pre>
-<h2 id="revision-specifier"><a class="header" href="#revision-specifier">Revision Specifier</a></h2>
-<pre><code class="language-markdown">  HEAD ........ last commit
-  HEAD~1 ...... last commit-1
-  HEAD~N ...... last commit-N (linear backwards when in tree structure, check
-                difference between HEAD^ and HEAD~)
-  git rev-list --max-parents=0 HEAD ........... first commit
+<h2 id="examples-4"><a class="header" href="#examples-4">Examples</a></h2>
+<h3 id="to-lower"><a class="header" href="#to-lower">To lower</a></h3>
+<pre><code class="language-sh">echo MoOsE | tr '[:upper:]' '[:lower:]'
+# output: moose
 </code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="awk1"><a class="header" href="#awk1">awk(1)</a></h1>
-<pre><code class="language-markdown">awk [opt] program [input]
-    -F &lt;sepstr&gt;        field separator string (can be regex)
-    program            awk program
-    input              file or stdin if not file given
+<h3 id="replace-characters"><a class="header" href="#replace-characters">Replace characters</a></h3>
+<pre><code class="language-sh">echo moose | tr 'o' '-'
+# output: m--se
+
+echo moose | tr 'os' '-'
+# output: m---e
 </code></pre>
-<h2 id="input-processing"><a class="header" href="#input-processing">Input processing</a></h2>
-<p>Input is processed in two stages:</p>
-<ol>
-<li>Splitting input into a sequence of <code>records</code>.
-By default split at <code>newline</code> character, but can be changed via the
-builtin <code>RS</code> variable.</li>
-<li>Splitting a <code>record</code> into <code>fields</code>. By default strings without <code>whitespace</code>,
-but can be changed via the builtin variable <code>FS</code> or command line option
-<code>-F</code>.</li>
-</ol>
-<p>Fields are accessed as follows:</p>
-<ul>
-<li><code>$0</code> whole <code>record</code></li>
-<li><code>$1</code> field one</li>
-<li><code>$2</code> field two</li>
-<li>...</li>
-</ul>
-<h2 id="program"><a class="header" href="#program">Program</a></h2>
-<p>An <code>awk</code> program is composed of pairs of the form:</p>
-<pre><code class="language-markdown">pattern { action }
+<h3 id="remove-specific-characters"><a class="header" href="#remove-specific-characters">Remove specific characters</a></h3>
+<pre><code class="language-sh">echo moose | tr -d 'o'
+# output: mse
+
+echo moose | tr -d 'os'
+# output: me
 </code></pre>
-<p>The program is run against each <code>record</code> in the input stream. If a <code>pattern</code>
-matches a <code>record</code> the corresponding <code>action</code> is executed and can access the
-<code>fields</code>.</p>
-<pre><code class="language-markdown">INPUT
-  |
-  v
-record ----&gt; ∀ pattern matched
-  |                   |
-  v                   v
-fields ----&gt; run associated action
+<h3 id="squeeze-character-sequences"><a class="header" href="#squeeze-character-sequences">Squeeze character sequences</a></h3>
+<pre><code class="language-sh">echo moooooossse | tr -s 'os'
+# output: mose
 </code></pre>
-<p>Any valid awk <code>expr</code> can be a <code>pattern</code>.</p>
-<p>An example is the regex pattern <code>/abc/ { print $1 }</code> which prints the first
-field if the record matches the regex <code>/abc/</code>. This form is actually a short
-version for <code>$0 ~ /abc/ { print $1 }</code>, see the regex comparison operator
-below.</p>
-<h3 id="special-pattern"><a class="header" href="#special-pattern">Special pattern</a></h3>
-<p>awk provides two special patterns, <code>BEGIN</code> and <code>END</code>, which can be used
-multiple times. Actions with those patterns are <strong>executed exactly once</strong>.</p>
-<ul>
-<li><code>BEGIN</code> actions are run before processing the first record</li>
-<li><code>END</code> actions are run after processing the last record</li>
-</ul>
-<h3 id="special-variables"><a class="header" href="#special-variables">Special variables</a></h3>
-<ul>
-<li><code>RS</code> <em>record separator</em>: first char is the record separator, by default
-<newline></li>
-<li><code>FS</code> <em>field separator</em>: regex to split records into fields, by default
-<space></li>
-<li><code>NR</code> <em>number record</em>: number of current record</li>
-<li><code>NF</code> <em>number fields</em>: number of fields in the current record</li>
-</ul>
-<h3 id="special-statements--functions"><a class="header" href="#special-statements--functions">Special statements &amp; functions</a></h3>
-<ul>
-<li>
-<p><code>printf "fmt", args...</code></p>
-<p>Print format string, args are comma separated.</p>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="tools"><a class="header" href="#tools">Tools</a></h1>
 <ul>
-<li><code>%s</code> string</li>
-<li><code>%d</code> decimal</li>
-<li><code>%x</code> hex</li>
-<li><code>%f</code> float</li>
+<li><a href="tools/./tmux.html">tmux</a></li>
+<li><a href="tools/./emacs.html">emacs</a></li>
+<li><a href="tools/./gpg.html">gpg</a></li>
+<li><a href="tools/./radare2.html">radare2</a></li>
+<li><a href="tools/./qemu.html">qemu</a></li>
+<li><a href="tools/./pacman.html">pacman</a></li>
+<li><a href="tools/./dot.html">dot</a></li>
+<li><a href="tools/./ffmpeg.html">ffmpeg</a></li>
+<li><a href="tools/./gnuplot.html">gnuplot</a></li>
+<li><a href="tools/./restic.html">restic</a></li>
 </ul>
-<p>Width can be specified as <code>%Ns</code>, this reserves <code>N</code> chars for a string.
-For floats one can use <code>%N.Mf</code>, <code>N</code> is the total number including <code>.</code> and
-<code>M</code>.</p>
-</li>
-<li>
-<p><code>sprintf("fmt", expr, ...)</code></p>
-<p>Format the expressions according to the format string. Similar as <code>printf</code>,
-but this is a function and return value can be assigned to a variable.</p>
-</li>
-<li>
-<p><code>strftime("fmt")</code></p>
-<p>Print time stamp formatted by <code>fmt</code>.</p>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="tmux1"><a class="header" href="#tmux1">tmux(1)</a></h1>
+<p>Terminology:</p>
 <ul>
-<li><code>%Y</code> full year (eg 2020)</li>
-<li><code>%m</code> month (01-12)</li>
-<li><code>%d</code> day (01-31)</li>
-<li><code>%F</code> alias for <code>%Y-%m-%d</code></li>
-<li><code>%H</code> hour (00-23)</li>
-<li><code>%M</code> minute (00-59)</li>
-<li><code>%S</code> second (00-59)</li>
-<li><code>%T</code> alias for <code>%H:%M:%S</code></li>
-</ul>
-</li>
-<li>
-<p><code>S ~ R</code>, <code>S !~ R</code></p>
-<p>The regex comparison operator, where the former returns true if the string
-<code>S</code> matches the regex <code>R</code>, and the latter is the negated form.
-The regex can be either a
-<a href="https://www.gnu.org/software/gawk/manual/html_node/Regexp-Usage.html">constant</a>
-or <a href="https://www.gnu.org/software/gawk/manual/html_node/Computed-Regexps.html">dynamic</a>
-regex.</p>
-</li>
+<li><code>session</code> is a collection of pseudo terminals which can have multiple
+<code>windows</code></li>
+<li><code>window</code> uses the entire screen and can be split into rectangular <code>panes</code></li>
+<li><code>pane</code> is a single pseudo terminal instance</li>
 </ul>
-<h2 id="examples"><a class="header" href="#examples">Examples</a></h2>
-<h3 id="filter-records"><a class="header" href="#filter-records">Filter records</a></h3>
-<pre><code class="language-bash">awk 'NR%2 == 0 { print $0 }' &lt;file&gt;
+<h1 id="tmux-cli"><a class="header" href="#tmux-cli">Tmux cli</a></h1>
+<pre><code class="language-markdown"># Session
+tmux                        creates new session
+tmux ls                     list running sessions
+tmux kill-session -t &lt;s&gt;    kill running session &lt;s&gt;
+tmux attach -t &lt;s&gt; [-d]     attach to session &lt;s&gt;, detach other clients [-d]
+tmux detach -s &lt;s&gt;          detach all clients from session &lt;s&gt;
+
+# Environment
+tmux showenv -g             show global tmux environment variables
+tmux setenv -g &lt;var&gt; &lt;val&gt;  set variable in global tmux env
+
+# Misc
+tmux source-file &lt;file&gt;     source config &lt;file&gt;
+tmux lscm                   list available tmux commnds
+tmux show -g                show global tmux options
+tmux display &lt;msg&gt;          display message in tmux status line
 </code></pre>
-<p>The pattern <code>NR%2 == 0</code> matches every second record and the action <code>{ print $0 }</code>
-prints the whole record.</p>
-<h3 id="negative-patterns"><a class="header" href="#negative-patterns">Negative patterns</a></h3>
-<pre><code class="language-bash">awk '!/^#/ { print $1 }' &lt;file&gt;
+<h2 id="scripting"><a class="header" href="#scripting">Scripting</a></h2>
+<pre><code class="language-markdown"># Session
+tmux list-sessions -F '#S'           list running sessions, only IDs
+
+# Window
+tmux list-windows -F '#I' -t &lt;s&gt;     list window IDs for session &lt;s&gt;
+tmux selectw -t &lt;s&gt;:&lt;w&gt;              select window &lt;w&gt; in session &lt;s&gt;
+
+# Pane
+tmux list-panes -F '#P' -t &lt;s&gt;:&lt;w&gt;   list pane IDs for window &lt;w&gt; in session &lt;s&gt;
+tmux selectp -t &lt;s&gt;:&lt;w&gt;.&lt;p&gt;          select pane &lt;p&gt; in window &lt;w&gt; in session &lt;s&gt;
+
+# Run commands
+tmux send -t &lt;s&gt;:&lt;w&gt;.&lt;p&gt; "ls" C-m    send cmds/keys to pane
+tmux run -t &lt;p&gt; &lt;sh-cmd&gt;             run shell command &lt;sh-cmd&gt; in background and report output on pane -t &lt;p&gt;
 </code></pre>
-<p>Matches records not starting with <code>#</code>.</p>
-<h3 id="range-patterns"><a class="header" href="#range-patterns">Range patterns</a></h3>
-<pre><code class="language-bash">echo -e "a\nFOO\nb\nc\nBAR\nd" | \
-    awk '/FOO/,/BAR/ { print }'
+<p>For example cycle through all panes in all windows in all sessions:</p>
+<pre><code class="language-bash"># bash
+for s in $(tmux list-sessions -F '#S'); do
+    for w in $(tmux list-windows -F '#I' -t $s); do
+        for p in $(tmux list-panes -F '#P' -t $s:$w); do
+            echo $s:$w.$p
+        done
+    done
+done
 </code></pre>
-<p><code>/FOO/,/BAR/</code> define a range pattern of <code>begin_pattern, end_pattern</code>. When
-<code>begin_pattern</code> is matched the range is <strong>turned on</strong> and when the
-<code>end_pattern</code> is matched the range is <strong>turned off</strong>. This matches every record
-in the range <em>inclusive</em>.</p>
-<p>An <em>exclusive</em> range must be handled explicitly, for example as follows.</p>
-<pre><code class="language-bash">echo -e "a\nFOO\nb\nc\nBAR\nd" | \
-    awk '/FOO/,/BAR/ { if (!($1 ~ "FOO") &amp;&amp; !($1 ~ "BAR")) { print } }'
+<h1 id="bindings"><a class="header" href="#bindings">Bindings</a></h1>
+<pre><code class="language-markdown">prefix d    detach from current session
+prefix c    create new window
+prefix w    open window list
+prefix $    rename session
+prefix ,    rename window
+prefix .    move current window
 </code></pre>
-<h3 id="access-last-fields-in-records"><a class="header" href="#access-last-fields-in-records">Access last fields in records</a></h3>
-<pre><code class="language-bash">echo 'a b c d e f' | awk '{ print $NF $(NF-1) }'
+<p>Following bindings are specific to my <a href="https://github.com/johannst/dotfiles/blob/master/tmux.conf"><code>tmux.conf</code></a>:</p>
+<pre><code class="language-markdown">C-s         prefix
+
+# Panes
+prefix s    horizontal split
+prefix v    vertical split
+prefix f    toggle maximize/minimize current pane
+
+# Movement
+prefix Tab  toggle between window
+
+prefix h    move to pane left
+prefix j    move to pane down
+prefix k    move to pane up
+prefix l    move to pane right
+
+# Resize
+prefix C-h  resize pane left
+prefix C-j  resize pane down
+prefix C-k  resize pane up
+prefix C-l  resize pane right
+
+# Copy/Paste
+prefix C-v    enter copy mode
+prefix C-p    paste yanked text
+prefix C-b    open copy-buffer list
+
+# In Copy Mode
+v     enable visual mode
+y     yank selected text
 </code></pre>
-<p>Access last fields with arithmetic on the <code>NF</code> number of fields variable.</p>
-<h3 id="split-on-multiple-tokens"><a class="header" href="#split-on-multiple-tokens">Split on multiple tokens</a></h3>
-<pre><code class="language-bash">echo 'a,b;c:d' | awk -F'[,;:]' '{ printf "1=%s | 4=%s\n", $1, $4 }'
+<h1 id="command-mode"><a class="header" href="#command-mode">Command mode</a></h1>
+<p>To enter command mode <code>prefix :</code>.</p>
+<p>Some useful commands are:</p>
+<pre><code class="language-markdown">setw synchronize-panes on/off       enables/disables synchronized input to all panes
+list-keys -t vi-copy                list keymaps for vi-copy mode
 </code></pre>
-<p>Use regex as field separator.</p>
-<h3 id="capture-in-variables"><a class="header" href="#capture-in-variables">Capture in variables</a></h3>
-<pre><code class="language-bash"># /proc/&lt;pid&gt;/status
-#   Name:    cat
-#   ...
-#   VmRSS:   516 kB
-#   ...
-
-for f in /proc/*/status; do
-    cat $f | awk '
-             /^VmRSS/ { rss = $2/1024 }
-             /^Name/ { name = $2 }
-             END { printf "%16s %6d MB\n", name, rss }';
-done | sort -k2 -n
-</code></pre>
-<p>We capture values from <code>VmRSS</code> and <code>Name</code> into variables and print them at the
-<code>END</code> once processing all records is done.</p>
-<h3 id="capture-in-array"><a class="header" href="#capture-in-array">Capture in array</a></h3>
-<pre><code class="language-bash">echo 'a 10
-b 2
-b 4
-a 1' | awk '{
-    vals[$1] += $2
-    cnts[$1] += 1
-}
-END {
-    for (v in vals)
-        printf "%s %d\n", v, vals[v] / cnts [v]
-}'
-</code></pre>
-<p>Capture keys and values from different columns and some up the values.
-At the <code>END</code> we compute the average of each key.</p>
-<h3 id="run-shell-command-and-capture-output"><a class="header" href="#run-shell-command-and-capture-output">Run shell command and capture output</a></h3>
-<pre><code class="language-bash">cat /proc/1/status | awk '
-                     /^Pid/ {
-                        "ps --no-header -o user " $2 | getline user;
-                         print user
-                     }'
-</code></pre>
-<p>We build a <code>ps</code> command line and capture the first line of the processes output
-in the <code>user</code> variable and then print it.</p>
 <div style="break-before: page; page-break-before: always;"></div><h1 id="emacs1"><a class="header" href="#emacs1">emacs(1)</a></h1>
 <h2 id="help"><a class="header" href="#help">help</a></h2>
 <pre><code class="language-markdown">  C-h ?         list available help modes
@@ -1597,7 +1560,7 @@ in the <code>user</code> variable and then print it.</p>
   &lt;f1&gt;             get doc for completion condidate
   M-&lt;digit&gt;        select completion candidate
 </code></pre>
-<h2 id="tags-1"><a class="header" href="#tags-1">tags</a></h2>
+<h2 id="tags"><a class="header" href="#tags">tags</a></h2>
 <p>To generate <code>etags</code> using <code>ctags</code></p>
 <pre><code class="language-markdown">  ctags -R -e .         generate emacs tag file (important `-e`)
 </code></pre>
@@ -1752,7 +1715,7 @@ gpg --verify &lt;file&gt;.asc &lt;file&gt;
 <li>http://keyserver.ubuntu.com</li>
 <li>hkps://pgp.mailbox.org</li>
 </ul>
-<h2 id="examples-1"><a class="header" href="#examples-1">Examples</a></h2>
+<h2 id="examples-5"><a class="header" href="#examples-5">Examples</a></h2>
 <h3 id="list-basic-key-information-from-file-with-long-keyids"><a class="header" href="#list-basic-key-information-from-file-with-long-keyids">List basic key information from file with long keyids</a></h3>
 <pre><code class="language-bash">gpg --keyid-format 0xlong &lt;key.asc&gt;
 </code></pre>
@@ -1769,1604 +1732,1487 @@ gpg&gt; save
 
 # Update keyserver(s) and/or export new pub keyfile.
 </code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="gdb1"><a class="header" href="#gdb1">gdb(1)</a></h1>
-<h1 id="cli"><a class="header" href="#cli">CLI</a></h1>
-<pre><code class="language-markdown">  gdb [opts] [prg [-c coredump | -p pid]]
-  gdb [opts] --args prg &lt;prg-args&gt;
-    opts:
-      -p &lt;pid&gt;        attach to pid
-      -c &lt;coredump&gt;   use &lt;coredump&gt;
-      -x &lt;file&gt;       execute script &lt;file&gt; before prompt
-      -ex &lt;cmd&gt;       execute command &lt;cmd&gt; before prompt
-      --tty &lt;tty&gt;     set I/O tty for debugee
-      --batch         run in batch mode, exit after processing options (eg used
-                      for scripting)
-      --batch-silent  link --batch, but surpress gdb stdout
+<div style="break-before: page; page-break-before: always;"></div><h1 id="radare21"><a class="header" href="#radare21">radare2(1)</a></h1>
+<h2 id="print"><a class="header" href="#print">print</a></h2>
+<pre><code class="language-markdown">
+  pd &lt;n&gt; [@ &lt;addr&gt;]     # print disassembly for &lt;n&gt; instructions
+                        # with optional temporary seek to &lt;addr&gt;
 </code></pre>
-<h1 id="interactive-usage"><a class="header" href="#interactive-usage">Interactive usage</a></h1>
-<h2 id="misc"><a class="header" href="#misc">Misc</a></h2>
-<pre><code class="language-markdown">  apropos &lt;regex&gt;
-          Search commands matching regex.
-
-  tty &lt;tty&gt;
-          Set &lt;tty&gt; as tty for debugee.
-          Make sure nobody reads from target tty, easiest is to spawn a shell
-          and run following in target tty:
-          &gt; while true; do sleep 1024; done
-
-  sharedlibrary [&lt;regex&gt;]
-          Load symbols of shared libs loaded by debugee. Optionally use &lt;regex&gt;
-          to filter libs for symbol loading.
-
-  display [/FMT] &lt;expr&gt;
-          Print &lt;expr&gt; every time debugee stops. Eg print next instr, see
-          examples below.
+<h2 id="flags"><a class="header" href="#flags">flags</a></h2>
+<pre><code class="language-markdown">  fs            # list flag-spaces
+  fs &lt;fs&gt;       # select flag-space &lt;fs&gt;
+  f             # print flags of selected flag-space
+</code></pre>
+<h2 id="help-1"><a class="header" href="#help-1">help</a></h2>
+<pre><code class="language-markdown">  ?*~&lt;kw&gt;       # '?*' list all commands and '~' grep for &lt;kw&gt;
+  ?*~...        # '..' less mode /'...' interactive search
+</code></pre>
+<h2 id="relocation"><a class="header" href="#relocation">relocation</a></h2>
+<pre><code class="language-markdown">  &gt; r2 -B &lt;baddr&gt; &lt;exe&gt;         # open &lt;exe&gt; mapped to addr &lt;baddr&gt;
+  oob &lt;addr&gt;                    # reopen current file at &lt;baddr&gt;
+</code></pre>
+<h1 id="examples-6"><a class="header" href="#examples-6">Examples</a></h1>
+<h2 id="patch-file-alter-bytes"><a class="header" href="#patch-file-alter-bytes">Patch file (alter bytes)</a></h2>
+<pre><code class="language-markdown">  &gt; r2 [-w] &lt;file&gt;
+  oo+           # re-open for write if -w was not passed
+  s &lt;addr&gt;      # seek to position
+  wv &lt;data&gt;     # write 4 byte (dword)
+</code></pre>
+<h2 id="assemble--disassmble-rasm2"><a class="header" href="#assemble--disassmble-rasm2">Assemble / Disassmble (rasm2)</a></h2>
+<pre><code class="language-markdown">  rasm2 -L      # list supported archs
 
-  undisplay [&lt;num&gt;]
-          Delete display expressions either all or one referenced by &lt;num&gt;.
+  &gt; rasm2 -a x86 'mov eax, 0xdeadbeef'
+  b8efbeadde
 
-  info display
-          List display expressions.
+  &gt; rasm2 -a x86 -d "b8efbeadde"
+  mov eax, 0xdeadbeef
+</code></pre>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="qemu1"><a class="header" href="#qemu1">qemu(1)</a></h1>
+<p>All the examples &amp; notes use <code>qemu-system-x86_64</code> but in most cases
+this can be swapped with the system emulator for other architectures.</p>
+<h2 id="keybindings-1"><a class="header" href="#keybindings-1">Keybindings</a></h2>
+<p>Graphic mode:</p>
+<pre><code class="language-markdown">Ctrl+Alt+g         release mouse capture from VM
 
-  info sharedlibrary [&lt;regex&gt;]
-          List shared libraries loaded. Optionally use &lt;regex&gt; to filter.
+Ctrl+Alt+1         switch to display of VM
+Ctrl+Alt+2         switch to qemu monitor
 </code></pre>
-<h2 id="breakpoints"><a class="header" href="#breakpoints">Breakpoints</a></h2>
-<pre><code class="language-markdown">  break [-qualified] &lt;sym&gt; thread &lt;tnum&gt;
-          Set a breakpoint only for a specific thread.
-          -qualified: Treat &lt;sym&gt; as fully qualified symbol (quiet handy to set
-          breakpoints on C symbols in C++ contexts)
+<p>No graphic mode:</p>
+<pre><code class="language-markdown">Ctrl+a h           print help
+Ctrl+a x           exit emulator
+Ctrl+a c           switch between monitor and console
+</code></pre>
+<h2 id="vm-config-snippet"><a class="header" href="#vm-config-snippet">VM config snippet</a></h2>
+<p>Following command-line gives a good starting point to assemble a VM:</p>
+<pre><code>qemu-system-x86_64                 \
+    -cpu host -enable-kvm -smp 4   \
+    -m 8G                          \
+    -vga virtio -display sdl,gl=on \
+    -boot menu=on                  \
+    -cdrom &lt;iso&gt;                   \
+    -hda &lt;disk&gt;                    \
+    -device qemu-xhci,id=xhci      \
+    -device usb-host,bus=xhci.0,vendorid=0x05e1,productid=0x0408,id=capture-card
+</code></pre>
+<h3 id="cpu--ram"><a class="header" href="#cpu--ram">CPU &amp; RAM</a></h3>
+<pre><code class="language-bash"># Emulate host CPU in guest VM, enabling all supported host featured (requires KVM).
+# List available CPUs `qemu-system-x86_64 -cpu help`.
+-cpu host
 
-  break &lt;sym&gt; if &lt;cond&gt;
-          Set conditional breakpoint (see examples below).
+# Enable KVM instead software emulation.
+-enable-kvm
 
-  delete [&lt;num&gt;]
-          Delete breakpoint either all or one referenced by &lt;num&gt;.
+# Configure number of guest CPUs.
+-smp &lt;N&gt;
 
-  info break
-          List breakpoints.
+# Configure size of guest RAM.
+-m 8G
+</code></pre>
+<h3 id="graphic--display"><a class="header" href="#graphic--display">Graphic &amp; Display</a></h3>
+<pre><code class="language-bash"># Use sdl window as display and enable openGL context.
+-display sdl,gl=on
 
-  cond &lt;bp&gt; &lt;cond&gt;
-          Make existing breakpoint &lt;bp&gt; conditional with &lt;cond&gt;.
+# Use vnc server as display (eg on display `:42` here).
+-display vnc=localhost:42
 
-  cond &lt;bp&gt;
-          Remove condition from breakpoint &lt;bp&gt;.
+# Confifure virtio as 3D video graphic accelerator (requires virgl in guest).
+-vga virtio
+</code></pre>
+<h3 id="boot-menu"><a class="header" href="#boot-menu">Boot Menu</a></h3>
+<pre><code class="language-bash"># Enables boot menu to select boot device (enter with `ESC`).
+-boot menu=on
+</code></pre>
+<h3 id="block-devices"><a class="header" href="#block-devices">Block devices</a></h3>
+<pre><code class="language-bash"># Attach cdrom drive with iso to a VM.
+-cdrom &lt;iso&gt;
 
-  tbreak
-          Set temporary breakpoint, will be deleted when hit.
-          Same syntax as `break`.
+# Attach disk drive to a VM.
+-hda &lt;disk&gt;
 
-  rbreak &lt;regex&gt;
-          Set breakpoints matching &lt;regex&gt;, where matching internally is done
-          on: .*&lt;regex&gt;.*
+# Generic way to configure &amp; attach a drive to a VM.
+-drive file=&lt;file&gt;,format=qcow2
+</code></pre>
+<h4 id="create-a-disk-with-qemu-img"><a class="header" href="#create-a-disk-with-qemu-img">Create a disk with <a href="https://qemu-project.gitlab.io/qemu/tools/qemu-img.html"><code>qemu-img</code></a></a></h4>
+<p>To create a <code>qcow2</code> disk (qemu copy-on-write) of size <code>10G</code>:</p>
+<pre><code class="language-bash">qemu-img create -f qcow2 disk.qcow2 10G
+</code></pre>
+<p>The disk does not contain any <code>partitions</code> or a <code>partition table</code>.
+We can format the disk from <strong>within the <strong>guest</strong></strong> as following example:</p>
+<pre><code class="language-bash"># Create `gpt` partition table.
+sudo parted /dev/sda mktable gpt
 
-  command [&lt;bp_list&gt;]
-          Define commands to run after breakpoint hit. If &lt;bp_list&gt; is not
-          specified attach command to last created breakpoint. Command block
-          terminated with 'end' token.
+# Create two equally sized primary partitions.
+sudo parted /dev/sda mkpart primary 0% 50%
+sudo parted /dev/sda mkpart primary 50% 100%
 
-          &lt;bp_list&gt;: Space separates list, eg 'command 2 5-8' to run command
-          for breakpoints: 2,5,6,7,8.
+# Create filesystem on each partition.
+sudo mkfs.ext3 /dev/sda1
+sudo mkfs.ext4 /dev/sda2
 
-  save break &lt;file&gt;
-          Save breakpoints to &lt;file&gt;. Can be loaded with the `source` command.
+lsblk -f /dev/sda
+  NAME   FSTYPE LABEL UUID FSAVAIL FSUSE% MOUNTPOINT
+  sda
+  ├─sda1 ext3         ....
+  └─sda2 ext4         ....
 </code></pre>
-<h2 id="watchpoints"><a class="header" href="#watchpoints">Watchpoints</a></h2>
-<pre><code class="language-markdown">  watch [-location|-l] &lt;expr&gt; [thread &lt;tnum&gt;]
-          Create a watchpoint for &lt;expr&gt;, will break if &lt;expr&gt; is written to.
-          Watchpoints respect scope of variables, -l can be used to watch the
-          memory location instead.
-
-  rwatch ...
-          Sets a read watchpoint, will break if &lt;expr&gt; is read from.
+<h3 id="usb"><a class="header" href="#usb">USB</a></h3>
+<h4 id="host-controller"><a class="header" href="#host-controller">Host Controller</a></h4>
+<pre><code class="language-bash"># Add XHCI USB controller to the VM (supports USB 3.0, 2.0, 1.1).
+# `id=xhci` creates a usb bus named `xhci`.
+-device qemu-xhci,id=xhci
+</code></pre>
+<h4 id="usb-device"><a class="header" href="#usb-device">USB Device</a></h4>
+<pre><code class="language-bash"># Pass-through USB device from host identified by vendorid &amp; productid and
+# attach to usb bus `xhci.0` (defined with controller `id`).
+-device usb-host,bus=xhci.0,vendorid=0x05e1,productid=0x0408
+</code></pre>
+<h2 id="debugging"><a class="header" href="#debugging">Debugging</a></h2>
+<pre><code class="language-bash"># Open gdbstub on tcp `&lt;port&gt;` (`-s` shorthand for `-gdb tcp::1234`).
+-gdb tcp::&lt;port&gt;
 
-  awatch ...
-          Sets an access watchpoint, will break if &lt;expr&gt; is written to or read
-          from.
+# Freeze guest CPU at startup and wait for debugger connection.
+-S
 </code></pre>
-<h2 id="catchpoints"><a class="header" href="#catchpoints">Catchpoints</a></h2>
-<pre><code class="language-markdown">  catch load [&lt;regex&gt;]
-          Stop when shared libraries are loaded, optionally specify a &lt;regex&gt;
-          to stop only on matches.
-  catch unload [&lt;regex&gt;]
-          Stop when shared libraries are unloaded, optionally specify a &lt;regex&gt;
-          to stop only on matches.
+<h2 id="io-redirection-2"><a class="header" href="#io-redirection-2">IO redirection</a></h2>
+<pre><code class="language-bash"># Create raw tcp server for `serial IO` and wait until a client connects
+# before executing the guest.
+-serial tcp:localhost:12345,server,wait
 
-  catch throw
-          Stop when an exception is thrown.
-  catch rethrow
-          Stop when an exception is rethrown.
-  catch catch
-          Stop when an exception is caught.
+# Create telnet server for `serial IO` and wait until a client connects
+# before executing the guest.
+-serial telnet:localhost:12345,server,wait
 
-  catch fork
-          Stop at calls to fork (also stops at clones, as some systems
-          implement fork via clone).
-
-  catch syscall [&lt;syscall&gt; &lt;syscall&gt; ..]
-          Stop at syscall. If no argument is given, stop at all syscalls.
-          Optionally give a list of syscalls to stop at.
+# Configure redirection for the QEMU `mointor`, arguments similar to `-serial`
+# above.
+-monitor ...
 </code></pre>
-<h2 id="inspection-1"><a class="header" href="#inspection-1">Inspection</a></h2>
-<pre><code class="language-markdown">  info functions [&lt;regex&gt;]
-          List functions matching &lt;regex&gt;. List all functions if no &lt;regex&gt;
-          provided.
-
-  info variables [&lt;regex&gt;]
-          List variables matching &lt;regex&gt;. List all variables if no &lt;regex&gt;
-          provided.
-
-  info register [&lt;reg&gt; &lt;reg&gt; ..]
-          Dump content of all registers or only the specified &lt;reg&gt;ister.
+<blockquote>
+<p>In <code>server</code> mode use <code>nowait</code> to execute guest without waiting for a client
+connection.</p>
+</blockquote>
+<h2 id="network"><a class="header" href="#network">Network</a></h2>
+<pre><code class="language-bash"># Redirect host tcp port `1234` to guest port `4321`.
+-nic user,hostfwd=tcp:localhost:1234-:4321
 </code></pre>
-<h2 id="signal-handling"><a class="header" href="#signal-handling">Signal handling</a></h2>
-<pre><code class="language-markdown">  info handle [&lt;signal&gt;]
-          Print how to handle &lt;signal&gt;. If no &lt;signal&gt; specified print for all
-          signals.
-
-  handle &lt;signal&gt; &lt;action&gt;
-          Configure how gdb handles &lt;signal&gt; sent to debugee.
-          &lt;action&gt;:
-            stop/nostop       Catch signal in gdb and break.
-            print/noprint     Print message when gdb catches signal.
-            pass/nopass       Pass signal down to debugee.
-
-  catch signal &lt;signal&gt;
-          Create a catchpoint for &lt;signal&gt;.
+<h2 id="shared-drives"><a class="header" href="#shared-drives">Shared drives</a></h2>
+<pre><code class="language-bash"># Attach a `virtio-9p-pci` device to the VM.
+# The guest requires 9p support and can mount the shared drive as:
+#   mount -t 9p -o trans=virtio someName /mnt
+-virtfs local,id=someName,path=&lt;someHostPath&gt;,mount_tag=someName,security_model=none
 </code></pre>
-<h2 id="multi-threading"><a class="header" href="#multi-threading">Multi-threading</a></h2>
-<pre><code class="language-markdown">info thread
-          List all threads.
+<h2 id="debug-logging"><a class="header" href="#debug-logging">Debug logging</a></h2>
+<pre><code class="language-bash"># List debug items.
+-d help
 
-thread apply &lt;id&gt; [&lt;id&gt;] &lt;command&gt;
-          Run command on all threads listed by &lt;id&gt; (space separated list).
-          When 'all' is specified as &lt;id&gt; the &lt;command&gt; is run on all threads.
+# Write debug log to file instead stderr.
+-D &lt;file&gt;
 
-thread name &lt;name&gt;
-          The &lt;name&gt; for the current thread.
+# Examples
+-d in_asm       Log executed guest instructions.
 </code></pre>
-<h2 id="multi-process"><a class="header" href="#multi-process">Multi-process</a></h2>
-<pre><code class="language-markdown">  set follow-fork-mode &lt;child | parent&gt;
-          Specify which process to follow when debuggee makes a fork(2)
-          syscall.
-
-  set detach-on-fork &lt;on | off&gt;
-          Turn on/off detaching from new child processes (on by default).
-          Turning this off allows to debug multiple processes (inferiors) with
-          one gdb session.
+<h2 id="tracing"><a class="header" href="#tracing">Tracing</a></h2>
+<pre><code class="language-bash"># List name of all trace points.
+-trace help
 
-  info inferiors
-          List all processes gdb debugs.
+# Enable trace points matching pattern and optionally write trace to file.
+-trace &lt;pattern&gt;[,file=&lt;file&gt;]
 
-  inferior &lt;id&gt;
-          Switch to inferior with &lt;id&gt;.
-</code></pre>
-<h2 id="scheduling"><a class="header" href="#scheduling">Scheduling</a></h2>
-<pre><code class="language-markdown">  set schedule-multiple &lt;on | off&gt;
-          on: Resume all threads of all processes (inferiors) when continuing
-              or stepping.
-          off: (default) Resume only threads of current process (inferior).
+# Enable trace points for all events listed in the &lt;events&gt; file.
+# File must contain one event/pattern per line.
+-trace events=&lt;events&gt;
 </code></pre>
-<h2 id="shell-commands"><a class="header" href="#shell-commands">Shell commands</a></h2>
-<pre><code class="language-markdown">  shell &lt;shell_cmd&gt;
-          Run the shell_cmd and print the output, can also contain a pipeline.
+<h2 id="vm-snapshots"><a class="header" href="#vm-snapshots">VM snapshots</a></h2>
+<p>VM snapshots require that there is at least on <code>qcow2</code> disk attached to the VM
+(<a href="https://qemu-project.gitlab.io/qemu/system/images.html#vm-005fsnapshots">VM Snapshots</a>).</p>
+<p>Commands for qemu <a href="https://qemu-project.gitlab.io/qemu/system/monitor.html">Monitor</a> or <a href="https://qemu-project.gitlab.io/qemu/interop/qemu-qmp-ref.html">QMP</a>:</p>
+<pre><code class="language-bash"># List available snapshots.
+info snapshots
 
-  pipe &lt;gdb_cmd&gt; | &lt;shell_cmd&gt;
-          Evaluate the gdb_cmd and run the shell_cmd which receives the output
-          of the gdb_cmd via stdin.
+# Create/Load/Delete snapshot with name &lt;tag&gt;.
+savevm &lt;tag&gt;
+loadvm &lt;tag&gt;
+delvm &lt;tag&gt;
 </code></pre>
-<h2 id="source-file-locations"><a class="header" href="#source-file-locations">Source file locations</a></h2>
-<pre><code class="language-markdown">  dir &lt;path&gt;
-          Add &lt;path&gt; to the beginning of the searh path for source files.
-
-  show dir
-          Show current search path.
-
-  set substitute-path &lt;from&gt; &lt;to&gt;
-          Add substitution rule checked during source file lookup.
-
-  show substitute-path
-          Show current substitution rules.
+<p>The snapshot can also be directly specified when invoking qemu as:</p>
+<pre><code class="language-bash">qemu-system-x86_64 \
+    -loadvm &lt;tag&gt;  \
+    ...
 </code></pre>
-<h2 id="configuration"><a class="header" href="#configuration">Configuration</a></h2>
-<pre><code class="language-markdown">  set disassembly-flavor &lt;intel | att&gt;
-          Set the disassembly style "flavor".
-
-  set pagination &lt;on | off&gt;
-          Turn on/off gdb's pagination.
-
-  set breakpoint pending &lt;on | off | auto&gt;
-          on: always set pending breakpoints.
-          off: error when trying to set pending breakpoints.
-          auto: interatively query user to set breakpoint.
-
-  set print pretty &lt;on | off&gt;
-          Turn on/off pertty printing of structures.
-
-  set style enabled &lt;on | off&gt;
-          Turn on/off styling (eg colored output).
-
-  set logging &lt;on | off&gt;
-          Enable output logging to file (default gdb.txt).
-
-  set logging file &lt;fname&gt;
-          Change output log file to &lt;fname&gt;
+<h2 id="vm-migration"><a class="header" href="#vm-migration">VM Migration</a></h2>
+<p><code>Online</code> migration example:</p>
+<pre><code class="language-bash"># Start machine 1 on host ABC.
+qemu-system-x86_64 -monitor stdio -cdrom &lt;iso&gt;
 
-  set logging redirect &lt;on | off&gt;
-          on: only log to file.
-          off: log to file and tty.
+# Prepare machine 2 on host DEF as migration target.
+# Listen for any connection on port 12345.
+qemu-system-x86_64 -monitor stdio -incoming tcp:0.0.0.0:12345
 
-  set logging overwrite &lt;on | off&gt;
-          on: Truncate log file on each run.
-          off: Append to logfile (default).
+# Start migration from the machine 1 monitor console.
+(qemu) migrate tcp:DEF:12345
+</code></pre>
+<p>Save to external file example:</p>
+<pre><code class="language-bash">```bash
+# Start machine 1.
+qemu-system-x86_64 -monitor stdio -cdrom &lt;iso&gt;
 
-  set history filename &lt;fname&gt;
-          Change file where to save and restore command history to and from.
+# Save VM state to file.
+(qemu) migrate "exec:gzip -c &gt; vm.gz"
 
-  set history &lt;on | off&gt;
-          Enable or disable saving of command history.
+# Load VM from file.
+qemu-system-x86_64 -monitor stdio -incoming "exec: gzip -d -c vm.gz"
 </code></pre>
 <blockquote>
-<p>Logging options should be configured before logging is turned on.</p>
+<p>The migration source machine and the migration target machine should be
+launched with the <strong>same</strong> parameters.</p>
 </blockquote>
-<h1 id="text-user-interface-tui"><a class="header" href="#text-user-interface-tui">Text user interface (TUI)</a></h1>
-<pre><code class="language-markdown">  C-x a     Toggle UI.
-  C-l       Redraw UI (curses UI can be messed up after the debugee prints to
-            stdout/stderr).
-  C-x o     Change focus.
+<h2 id="appendix-direct-kernel-boot"><a class="header" href="#appendix-direct-kernel-boot">Appendix: Direct <code>Kernel</code> boot</a></h2>
+<p>Example command line to directly boot a <code>Kernel</code> with an <code>initrd</code> ramdisk.</p>
+<pre><code class="language-bash">qemu-system-x86_64                                                     \
+    -cpu host                                                          \
+    -enable-kvm                                                        \
+    -kernel &lt;dir&gt;/arch/x86/boot/bzImage                                \
+    -append "earlyprintk=ttyS0 console=ttyS0 nokaslr init=/init debug" \
+    -initrd &lt;dir&gt;/initramfs.cpio.gz                                    \
+    ...
 </code></pre>
-<h1 id="user-commands-macros"><a class="header" href="#user-commands-macros">User commands (macros)</a></h1>
-<p>Gdb allows to create &amp; document user commands as follows:</p>
-<pre><code class="language-markdown">  define &lt;cmd&gt;
-    # cmds
-  end
+<p>Instructions to build a minimal <a href="https://blog.memzero.de/kernel-debugging-qemu"><code>Kernel</code> and <code>initrd</code></a>.</p>
+<h2 id="appendix-cheap-instruction-tracer"><a class="header" href="#appendix-cheap-instruction-tracer">Appendix: Cheap instruction tracer</a></h2>
+<pre><code class="language-make">test: test.s
+	as -o test.o test.s
+	ld -o test test.o testc.o
 
-  document &lt;cmd&gt;
-    # docu
-  end
+trace: test
+	qemu-x86_64 -singlestep -d nochain,cpu ./test 2&gt;&amp;1 | awk '/RIP/ { print $$1; }'
+
+clean:
+	$(RM) test test-bin test.o
 </code></pre>
-<p>To get all user commands or documentations one can use:</p>
-<pre><code class="language-markdown">  help user-defined
-  help &lt;cmd&gt;
+<pre><code class="language-x86asm">.section .text, "ax"
+
+.global _start
+_start:
+    xor %rax, %rax
+    mov $0x8, %rax
+1:
+    cmp $0, %rax
+    je 2f
+    dec %rax
+    jmp 1b
+2:
+    # x86-64 exit(2) syscall
+    mov $0, %rdi
+    mov $60, %rax
+    syscall
 </code></pre>
-<h1 id="hooks"><a class="header" href="#hooks">Hooks</a></h1>
-<p>Gdb allows to create two types of command <code>hooks</code></p>
+<h2 id="references"><a class="header" href="#references">References</a></h2>
 <ul>
-<li><code>hook-</code> will be run before <code>&lt;cmd&gt;</code></li>
-<li><code>hookpost-</code> will be run after <code>&lt;cmd&gt;</code></li>
+<li><a href="https://github.com/qemu/qemu/blob/master/docs/usb2.txt">QEMU USB</a></li>
+<li><a href="https://qemu-project.gitlab.io/qemu/tools/qemu-img.html">QEMU IMG</a></li>
+<li><a href="https://qemu-project.gitlab.io/qemu/tools/index.html">QEMU Tools</a></li>
+<li><a href="https://qemu-project.gitlab.io/qemu/system/index.html">QEMU System</a></li>
+<li><a href="https://qemu-project.gitlab.io/qemu/system/invocation.html">QEMU Invocation (command line args)</a></li>
+<li><a href="https://qemu-project.gitlab.io/qemu/system/monitor.html">QEMU Monitor</a></li>
+<li><a href="https://qemu-project.gitlab.io/qemu/interop/qemu-qmp-ref.html">QEMU machine protocol (QMP)</a></li>
+<li><a href="https://qemu-project.gitlab.io/qemu/system/images.html#vm-005fsnapshots">QEMU VM Snapshots</a></li>
 </ul>
-<pre><code class="language-markdown">  define hook-&lt;cmd&gt;
-    # cmds
-  end
-
-  define hookpost-&lt;cmd&gt;
-    # cmds
-  end
+<div style="break-before: page; page-break-before: always;"></div><h1 id="pacman1"><a class="header" href="#pacman1">pacman(1)</a></h1>
+<h2 id="remote-package-repositories"><a class="header" href="#remote-package-repositories">Remote package repositories</a></h2>
+<pre><code class="language-text">pacman -Sy              refresh package database
+pacman -S &lt;pkg&gt;         install pkg
+pacman -Ss &lt;regex&gt;      search remote package database
+pacman -Si &lt;pkg&gt;        get info for pkg
+pacman -Su              upgrade installed packages
+pacman -Sc              clean local package cache
 </code></pre>
-<h1 id="examples-2"><a class="header" href="#examples-2">Examples</a></h1>
-<h2 id="automatically-print-next-instr"><a class="header" href="#automatically-print-next-instr">Automatically print next instr</a></h2>
-<p>When ever the debugee stops automatically print the memory at the current
-instruction pointer (<code>$rip</code> x86) and format as instruction <code>/i</code>.</p>
-<pre><code class="language-markdown">  # rip - x86
-  display /i $rip
-
-  # step instruction, after the step the next instruction is automatically printed
-  si
+<h2 id="remove-packages"><a class="header" href="#remove-packages">Remove packages</a></h2>
+<pre><code class="language-text">pacman -Rsn &lt;pkg&gt;               uninstall package and unneeded deps + config files
 </code></pre>
-<h2 id="conditional-breakpoints"><a class="header" href="#conditional-breakpoints">Conditional breakpoints</a></h2>
-<p>Create conditional breakpoints for a function <code>void foo(int i)</code> in the debugee.</p>
-<pre><code class="language-markdown">  # Create conditional breakpoint
-  b foo if i == 42
-
-  b foo     # would create bp 2
-  # Make existing breakpoint conditional
-  cond 2 i == 7
+<h2 id="local-package-database"><a class="header" href="#local-package-database">Local package database</a></h2>
+<p>Local package database of installed packages.</p>
+<pre><code class="language-text">pacman -Q               list all installed packages
+pacman -Qs &lt;regex&gt;      search local package database
+pacman -Ql &lt;pkg&gt;        list files installed by pkg
+pacman -Qo &lt;file&gt;       query package that owns file
+pacman -Qe              only list explicitly installed packages
 </code></pre>
-<h2 id="set-breakpoint-on-all-threads-except-one"><a class="header" href="#set-breakpoint-on-all-threads-except-one">Set breakpoint on all threads except one</a></h2>
-<p>Create conditional breakpoint using the <code>$_thread</code> <a href="https://sourceware.org/gdb/onlinedocs/gdb/Convenience-Vars.html#Convenience-Vars">convenience
-variable</a>.</p>
-<pre><code class="language-markdown">  # Create conditional breakpoint on all threads except thread 12.
-  b foo if $_thread != 12
+<h2 id="local-file-database"><a class="header" href="#local-file-database">Local file database</a></h2>
+<p>Local file database which allows to search packages owning certain files.
+Also searches non installed packages, but database must be synced.</p>
+<pre><code class="language-text">pacman -Fy              refresh file database
+pacman -Fl &lt;pkg&gt;        list files in pkg (must not be installed)
+pacman -Fx &lt;regex&gt;      search 
 </code></pre>
-<h2 id="catch-sigsegv-and-execute-commands"><a class="header" href="#catch-sigsegv-and-execute-commands">Catch SIGSEGV and execute commands</a></h2>
-<p>This creates a <code>catchpoint</code> for the <code>SIGSEGV</code> signal and attached the <code>command</code>
-to it.</p>
-<pre><code class="language-markdown">  catch signal SIGSEGV
-  command
-    bt
-    c
-  end
+<h2 id="hacks"><a class="header" href="#hacks">Hacks</a></h2>
+<p>Uninstall all orphaned packages (including config files) that were installed as
+dependencies.</p>
+<pre><code class="language-text">pacman -Rsn $(pacman -Qtdq)
 </code></pre>
-<h2 id="run-backtrace-on-thread-1-batch-mode"><a class="header" href="#run-backtrace-on-thread-1-batch-mode">Run <code>backtrace</code> on thread 1 (batch mode)</a></h2>
-<pre><code class="language-markdown">  gdb --batch -ex 'thread 1' -ex 'bt' -p &lt;pid&gt;
+<p>List explicitly installed packages that are not required as dependency by any
+package and sort by size.</p>
+<pre><code class="language-text">pacman -Qetq | xargs pacman -Qi |
+    awk '/Name/ { name=$3 }
+         /Installed Size/ { printf "%8.2f%s %s\n", $4, $5, name }' |
+    sort -h
 </code></pre>
-<h2 id="script-gdb-for-automating-debugging-sessions"><a class="header" href="#script-gdb-for-automating-debugging-sessions">Script gdb for automating debugging sessions</a></h2>
-<p>To script gdb add commands into a file and pass it to gdb via <code>-x</code>.
-For example create <code>run.gdb</code>:</p>
-<pre><code class="language-markdown">  set pagination off
-
-  break mmap
-  command
-    info reg rdi rsi rdx
-    bt
-    c
-  end
-
-  #initial drop
-  c
+<p>Install package into different <code>root</code> directory but keep using the default
+database.</p>
+<pre><code class="language-text">pacman --root abc --dbpath /var/lib/pacman -S mingw-w64-gcc
 </code></pre>
-<p>This script can be used as:</p>
-<pre><code class="language-markdown">  gdb --batch -x ./run.gdb -p &lt;pid&gt;
+<div style="break-before: page; page-break-before: always;"></div><h1 id="dot1"><a class="header" href="#dot1">dot(1)</a></h1>
+<p><a href="https://edotor.net/">Online playground</a></p>
+<h2 id="example-dot-file-to-copy--paste-from"><a class="header" href="#example-dot-file-to-copy--paste-from">Example <code>dot</code> file to copy &amp; paste from.</a></h2>
+<p>Can be rendered to <code>svg</code> with the following command.</p>
+<pre><code class="language-bash">dot -T svg -o g.svg g.dot
 </code></pre>
-<h2 id="hook-to-automatically-save-breakpoints-on-quit"><a class="header" href="#hook-to-automatically-save-breakpoints-on-quit">Hook to automatically save breakpoints on <code>quit</code></a></h2>
-<pre><code class="language-markdown">define break-save
-    save breakpoint $arg0.gdb.bp
-end
-define break-load
-    source $arg0.gdb.bp
-end
+<p>Example <code>dot</code> file.</p>
+<pre><code class="language-dot">// file: g.dot
+digraph {
+    // Render ranks from left to right.
+    rankdir=LR
+    // Make background transparent.
+    bgcolor=transparent
 
-define hook-quit
-    break-save quit
-end
-</code></pre>
-<h2 id="watchpoint-on-struct--class-member"><a class="header" href="#watchpoint-on-struct--class-member">Watchpoint on struct / class member</a></h2>
-<p>A symbolic watchpoint defined on a member variable for debugging is only valid
-as long as the expression is in scope. Once out of scope the watchpoint gets
-deleted.</p>
-<p>When debugging some memory corruption we want to keep the watchpoint even the
-expression goes out of scope to find the location that overrides the variable
-and introduces the corruption.</p>
-<pre><code class="language-markdown">(gdb) l
-1  struct S { int v; };
-2
-3  void set(struct S* s, int v) {
-4      s-&gt;v = v;
-5  }
-6
-7  int main() {
-8      struct S s;
-9      set(&amp;s, 1);
-10     set(&amp;s, 2);
-11     set(&amp;s, 3);
-...
+    // Global node attributes.
+    node [shape=box]
+    // Global edge attributes.
+    edge [style=dotted,color=red]
 
-(gdb) s
-set (s=0x7fffffffe594, v=1) at test.c:4
-4    s-&gt;v = v;
+    // Add nodes &amp; edge.
+    stage1 -&gt; stage2
+    // Add multiple edges at once.
+    stage2 -&gt; { stage3_1, stage3_2 }
+    // Add edge with custom attributes.
+    stage3_2 -&gt; stage4 [label="some text"]
 
-# Define a new watchpoint on the member of the struct. The expression however
-# is only valid in the current functions scope.
+    // Set custom attributes for specific node.
+    stage4 [color=green,fillcolor=lightgray,style="filled,dashed",label="s4"]
 
-(gdb) watch s-&gt;v
-Hardware watchpoint 2: s-&gt;v
+    // Create a subgraph. This can be used to group nodes/edges or as scope for
+    // global node/edge attributes.
+    // If the name starts with 'cluster' a border is drawn.
+    subgraph cluster_1 {
+        stage5_1
+        stage5_2
+    }
 
-(gdb) c
-Hardware watchpoint 2: s-&gt;v
-Old value = 0
-New value = 1
-set (s=0x7fffffffe594, v=1) at test.c:5
-5   }
+    // Add some edges to subgraph nodes.
+    stage3_1 -&gt; { stage5_1, stage5_2 }
+}
+</code></pre>
+<p>Rendered <code>svg</code> file.
+<img src="tools/assets/g.svg" alt="g.svg" /></p>
+<h2 id="references-1"><a class="header" href="#references-1">References</a></h2>
+<ul>
+<li><a href="https://graphviz.org/doc/info/lang.html">DOT language</a></li>
+<li><a href="https://graphviz.org/doc/info/attrs.html">Attributes</a></li>
+<li><a href="https://graphviz.org/doc/info/shapes.html">Node shapes</a></li>
+<li><a href="https://graphviz.org/doc/info/colors.html">Colors</a></li>
+<li><a href="https://graphviz.org/pdf/dotguide.pdf">User manual</a></li>
+</ul>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="ffmpeg-1"><a class="header" href="#ffmpeg-1">ffmpeg (1)</a></h1>
+<h2 id="screen-capture-specific-window-x11"><a class="header" href="#screen-capture-specific-window-x11">screen capture specific window (x11)</a></h2>
+<p>Following snippet allows to select a window which is then captured.</p>
+<pre><code class="language-bash">#!/bin/bash
 
-# The watchpoint gets deleted as soon as we leave the function scope.
+echo "Click on window to record .."
+# Extract window size and x,y offset.
+video_args=$(xwininfo \
+    | awk '/Absolute upper-left X:/ { xoff = $4 }
+           /Absolute upper-left Y:/ { yoff=$4 }
+           /Width:/ { if ($2 % 2 == 1) { width=$2-1; } else { width=$2; } }
+           /Height:/ { if ($2 % 2 == 1) { height=$2-1; } else { height=$2; } }
+           END { printf "-video_size %dx%d -i :0.0+%d,%d", width, height, xoff, yoff  }')
 
-(gdb) c
-Watchpoint 2 deleted because the program has left the block in
-which its expression is valid.
-main () at test.c:10
-10      set(&amp;s, 2);
+ffmpeg -framerate 25 -f x11grab $video_args -pix_fmt yuv420p $@ output.mp4
+</code></pre>
+<blockquote>
+<p>Use <code>yuv420p</code> pixel format if video is played on the web
+(<a href="https://stackoverflow.com/questions/32829514/which-pixel-format-for-web-mp4-video">ref</a>)</p>
+</blockquote>
+<p>The input <code>-i 0,0+xoff,yoff</code> means to capture <code>$DISPLAY=0.0</code> starting at the
+coordinate <code>(xoff, yoff)</code>, which is the left-upper corner, and the size of the
+capture is defined by the <code>-video_size</code> argument.</p>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="gnuplot-1"><a class="header" href="#gnuplot-1">gnuplot (1)</a></h1>
+<pre><code># Launch interactive shell.
+gnuplot
 
-# Define the watchpoint on the location of the object to watch.
+# Launch interactive shell.
+gnuplot [opt]
+  opt:
+    -p ................ persist plot window
+    -c &lt;file&gt; ......... run script file
+    -e "&lt;cmd1&gt;; .." ... run cmd(s)
+</code></pre>
+<h2 id="frequently-used-configuration"><a class="header" href="#frequently-used-configuration">Frequently used configuration</a></h2>
+<pre><code class="language-sh"># Plot title.
+set title "the plot"
 
-(gdb) watch -l s-&gt;v
+# Labels.
+set xlabel "abc"
+set ylabel "def"
 
-# This is equivalent to the following.
+# Output format, 'help set term' for all output formats.
+set term svg
+# Output file.
+set output "out.svg"
 
-(gdb) p &amp;s-&gt;v
-$1 = (int *) 0x7fffffffe594
+# Make axis logarithmic to given base.
+set logscale x 2
 
-# Define a watchpoint to the address of the member variable of the s instance.
-# This of course only makes sense as long as the s instance is not moved in memory.
+# Change separator, default is whitespace.
+set datafile separator ","
+</code></pre>
+<h2 id="plot"><a class="header" href="#plot">Plot</a></h2>
+<pre><code class="language-sh"># With specific style (eg lines, linespoint, boxes, steps, impulses, ..).
+plot "&lt;data_file&gt;" with &lt;plot_style&gt;
 
-(gdb) watch *0x7fffffffe594
-Hardware watchpoint 3: *0x7fffffffe594
+&gt; cat data.txt
+1 1 3
+2 2 2
+3 3 1
+4 2 2
 
-(gdb) c
-Hardware watchpoint 3: *0x7fffffffe594
-Old value = 1
-New value = 2
-set (s=0x7fffffffe594, v=2) at test.c:5
-5   }
+# Plot specific column.
+plot "data.txt" using 1:2, "data.txt" using 1:3
+# Equivalent using the special file "", which re-uses the previous input file.
+plot "data.txt" using 1:2, "" using 1:3
 
-(gdb) c
-Hardware watchpoint 3: *0x7fffffffe594
-Old value = 2
-New value = 3
-set (s=0x7fffffffe594, v=3) at test.c:5
-5   }
+# Plot piped data.
+plot "&lt; head -n2 data.txt"
+
+# Plot with alternate title.
+plot "data.txt" title "moose"
 </code></pre>
-<h2 id="shell-commands-1"><a class="header" href="#shell-commands-1">Shell commands</a></h2>
-<pre><code class="language-markdown"># Run shell commands.
+<h2 id="example-multiple-data-sets-in-plot"><a class="header" href="#example-multiple-data-sets-in-plot">Example: multiple data sets in plot</a></h2>
+<pre><code class="language-sh"># file: mem_lat.plot
 
-(gdb) shell zcat /proc/config.gz | grep CONFIG_KVM=
-CONFIG_KVM=m
+set title  "memory latency (different strides)"
+set xlabel "array in KB"
+set ylabel "cycles / access"
 
-# Pipe gdb command to shell command.
+set logscale x 2
 
-(gdb) pipe info proc mapping | grep libc
-    0x7ffff7a1a000     0x7ffff7a42000    0x28000        0x0  r--p   /usr/lib/libc.so.6
-    0x7ffff7a42000     0x7ffff7b9d000   0x15b000    0x28000  r-xp   /usr/lib/libc.so.6
-    0x7ffff7b9d000     0x7ffff7bf2000    0x55000   0x183000  r--p   /usr/lib/libc.so.6
-    0x7ffff7bf2000     0x7ffff7bf6000     0x4000   0x1d7000  r--p   /usr/lib/libc.so.6
-    0x7ffff7bf6000     0x7ffff7bf8000     0x2000   0x1db000  rw-p   /usr/lib/libc.so.6
+plot "stride_32.txt"  title "32"  with linespoints, \
+     "stride_64.txt"  title "64"  with linespoints, \
+     "stride_128.txt" title "128" with linespoints, \
+     "stride_256.txt" title "256" with linespoints, \
+     "stride_512.txt" title "512" with linespoints
 </code></pre>
-<h1 id="know-bugs"><a class="header" href="#know-bugs">Know Bugs</a></h1>
-<h2 id="workaround-command--finish-bug"><a class="header" href="#workaround-command--finish-bug">Workaround <code>command + finish</code> bug</a></h2>
-<p>When using <code>finish</code> inside a <code>command</code> block, commands after <code>finish</code> are not
-executed. To workaround that bug one can create a wrapper function which calls
-<code>finish</code>.</p>
-<pre><code class="language-markdown">  define handler
-    bt
-    finish
-    info reg rax
-  end
+<p>On Linux x86_64, <a href="tools/gnuplot/mem_lat.c"><code>mem_lat.c</code></a> provides an example which can
+be run as follows.</p>
+<pre><code class="language-sh">gcc -o mem_lat mem_lat.c -g -O3 -Wall -Werror
 
-  command
-    handler
-  end
-</code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="gdbserver1"><a class="header" href="#gdbserver1">gdbserver(1)</a></h1>
-<h1 id="cli-1"><a class="header" href="#cli-1">CLI</a></h1>
-<pre><code class="language-markdown">  gdbserver [opts] comm prog [args]
-    opts:
-      --disable-randomization
-      --no-disable-randomization
-      --wrapper W --
+for stride in 32 64 128 256 512; do \
+    taskset -c 1 ./mem_lat 128 $stride | tee stride_$stride.txt ; \
+done
 
-    comm:
-      host:port
-      tty
+gnuplot -p -c mem_lat.plot
 </code></pre>
-<h2 id="example-4"><a class="header" href="#example-4">Example</a></h2>
-<pre><code class="language-markdown"># Start gdbserver.
-gdbserver localhost:1234 /bin/ls
+<div style="break-before: page; page-break-before: always;"></div><h1 id="restic1"><a class="header" href="#restic1">restic(1)</a></h1>
+<h2 id="create-new-snapshot-repository"><a class="header" href="#create-new-snapshot-repository">Create new snapshot repository</a></h2>
+<pre><code class="language-bash"># Create a local backup repository.
+restic -r &lt;path&gt; init
 
-# Attach gdb.
-gdb -ex 'target remote localhost:1234'
+# Create a backup repository on a remote host.
+restic -r sftp:user@host:&lt;path&gt; init
 </code></pre>
-<h2 id="wrapper-example-set-environment-variables-just-for-the-debugee"><a class="header" href="#wrapper-example-set-environment-variables-just-for-the-debugee">Wrapper example: Set environment variables just for the debugee</a></h2>
-<p>Set <code>env</code> as execution wrapper with some variables.
-The wrapper will be executed before the debugee.</p>
-<pre><code class="language-markdown">gdbserver --wrapper env FOO=123 BAR=321 -- :12345 /bin/ls
+<h2 id="example-restore-file-pattern-from-latest-snapshot"><a class="header" href="#example-restore-file-pattern-from-latest-snapshot">Example: Restore file pattern from <code>latest</code> snapshot</a></h2>
+<p>Restore files matching <code>&lt;file_pattern&gt;</code> from the <code>latest</code> snapshot (pseudo
+snapshot ID) into <code>&lt;dest&gt;</code>.</p>
+<pre><code class="language-bash">restic -r &lt;repo&gt; restore -i &lt;file_pattern&gt; --target &lt;dest&gt; latest
 </code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="radare21"><a class="header" href="#radare21">radare2(1)</a></h1>
-<h2 id="print"><a class="header" href="#print">print</a></h2>
-<pre><code class="language-markdown">
-  pd &lt;n&gt; [@ &lt;addr&gt;]     # print disassembly for &lt;n&gt; instructions
-                        # with optional temporary seek to &lt;addr&gt;
+<h2 id="mount-snapshots"><a class="header" href="#mount-snapshots">Mount snapshots</a></h2>
+<p>Mount snapshots as user filesystem (fuse) to given mount point.</p>
+<pre><code class="language-bash">restic -r &lt;repo&gt; mount &lt;mntpoint&gt;
+
+# Mounted snapshots can be limited by host.
+restic -r &lt;repo&gt; mount --host &lt;host&gt; &lt;mntpoint&gt;
+
+# Mounted snapshots can be limited by path (abs path).
+restic -r &lt;repo&gt; mount --path &lt;abspath&gt; &lt;mntpoint&gt;
 </code></pre>
-<h2 id="flags"><a class="header" href="#flags">flags</a></h2>
-<pre><code class="language-markdown">  fs            # list flag-spaces
-  fs &lt;fs&gt;       # select flag-space &lt;fs&gt;
-  f             # print flags of selected flag-space
+<h2 id="repository-maintenance"><a class="header" href="#repository-maintenance">Repository maintenance</a></h2>
+<p>Check the repository for errors and report them.</p>
+<pre><code class="language-bash">restic -r &lt;repo&gt; check
 </code></pre>
-<h2 id="help-1"><a class="header" href="#help-1">help</a></h2>
-<pre><code class="language-markdown">  ?*~&lt;kw&gt;       # '?*' list all commands and '~' grep for &lt;kw&gt;
-  ?*~...        # '..' less mode /'...' interactive search
+<p>Check the repository for non-referenced data and remove it.</p>
+<pre><code class="language-bash">restic -r &lt;repo&gt; prune
 </code></pre>
-<h2 id="relocation"><a class="header" href="#relocation">relocation</a></h2>
-<pre><code class="language-markdown">  &gt; r2 -B &lt;baddr&gt; &lt;exe&gt;         # open &lt;exe&gt; mapped to addr &lt;baddr&gt;
-  oob &lt;addr&gt;                    # reopen current file at &lt;baddr&gt;
+<h2 id="references-2"><a class="header" href="#references-2">References</a></h2>
+<ul>
+<li><a href="https://restic.readthedocs.io/en/stable/index.html"><code>restic</code> read the docs</a></li>
+<li><a href="https://restic.readthedocs.io/en/stable/030_preparing_a_new_repo.html#sftp">sftp</a></li>
+</ul>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="resource-analysis--monitor"><a class="header" href="#resource-analysis--monitor">Resource analysis &amp; monitor</a></h1>
+<ul>
+<li><a href="monitor/./lsof.html">lsof</a></li>
+<li><a href="monitor/./pidstat.html">pidstat</a></li>
+<li><a href="monitor/./pgrep.html">pgrep</a></li>
+<li><a href="monitor/./ps.html">ps</a></li>
+<li><a href="monitor/./pmap.html">pmap</a></li>
+<li><a href="monitor/./pstack.html">pstack</a></li>
+</ul>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="lsof8"><a class="header" href="#lsof8">lsof(8)</a></h1>
+<pre><code class="language-markdown">lsof
+  -r &lt;s&gt; ..... repeatedly execute command ervery &lt;s&gt; seconds
+  -a ......... AND slection filters instead ORing (OR: default)
+  -p &lt;pid&gt; ... filter by &lt;pid&gt;
+  +fg ........ show file flags for file descripros
+  -n ......... don't convert network addr to hostnames
+  -P ......... don't convert network port to service names
+  -i &lt;@h[:p]&gt;. show connections to h (hostname|ip addr) with optional port p
+  -s &lt;p:s&gt; ... in conjunction with '-i' filter for protocol &lt;p&gt; in state &lt;s&gt;
+  -U ......... show unix domain sockets ('@' indicates abstract sock name, see unix(7))
 </code></pre>
-<h1 id="examples-3"><a class="header" href="#examples-3">Examples</a></h1>
-<h2 id="patch-file-alter-bytes"><a class="header" href="#patch-file-alter-bytes">Patch file (alter bytes)</a></h2>
-<pre><code class="language-markdown">  &gt; r2 [-w] &lt;file&gt;
-  oo+           # re-open for write if -w was not passed
-  s &lt;addr&gt;      # seek to position
-  wv &lt;data&gt;     # write 4 byte (dword)
+<pre><code class="language-markdown">file flags:
+  R/W/RW ..... read/write/read-write
+  CR ......... create
+  AP ......... append
+  TR ......... truncate
 </code></pre>
-<h2 id="assemble--disassmble-rasm2"><a class="header" href="#assemble--disassmble-rasm2">Assemble / Disassmble (rasm2)</a></h2>
-<pre><code class="language-markdown">  rasm2 -L      # list supported archs
+<pre><code class="language-markdown">-s protocols
+  TCP, UDP
 
-  &gt; rasm2 -a x86 'mov eax, 0xdeadbeef'
-  b8efbeadde
+-s states (TCP)
+  CLOSED, IDLE, BOUND, LISTEN, ESTABLISHED, SYN_SENT, SYN_RCDV, ESTABLISHED,
+  CLOSE_WAIT, FIN_WAIT1, CLOSING, LAST_ACK, FIN_WAIT_2, TIME_WAIT
 
-  &gt; rasm2 -a x86 -d "b8efbeadde"
-  mov eax, 0xdeadbeef
+-s states (UDP)
+  Unbound, Idle
 </code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="qemu1"><a class="header" href="#qemu1">qemu(1)</a></h1>
-<p>All the examples &amp; notes use <code>qemu-system-x86_64</code> but in most cases
-this can be swapped with the system emulator for other architectures.</p>
-<h2 id="keybindings-1"><a class="header" href="#keybindings-1">Keybindings</a></h2>
-<p>Graphic mode:</p>
-<pre><code class="language-markdown">Ctrl+Alt+g         release mouse capture from VM
-
-Ctrl+Alt+1         switch to display of VM
-Ctrl+Alt+2         switch to qemu monitor
+<h1 id="examples-7"><a class="header" href="#examples-7">Examples</a></h1>
+<h2 id="file-flags"><a class="header" href="#file-flags">File flags</a></h2>
+<p>Show open files with file flags for process:</p>
+<pre><code class="language-markdown">lsof +fg -p &lt;pid&gt;
 </code></pre>
-<p>No graphic mode:</p>
-<pre><code class="language-markdown">Ctrl+a h           print help
-Ctrl+a x           exit emulator
-Ctrl+a c           switch between monitor and console
+<h2 id="open-tcp-connections"><a class="header" href="#open-tcp-connections">Open TCP connections</a></h2>
+<p>Show open tcp connections for <code>$USER</code>:</p>
+<pre><code class="language-markdown">lsof -a -u $USER -i TCP
 </code></pre>
-<h2 id="vm-config-snippet"><a class="header" href="#vm-config-snippet">VM config snippet</a></h2>
-<p>Following command-line gives a good starting point to assemble a VM:</p>
-<pre><code>qemu-system-x86_64                 \
-    -cpu host -enable-kvm -smp 4   \
-    -m 8G                          \
-    -vga virtio -display sdl,gl=on \
-    -boot menu=on                  \
-    -cdrom &lt;iso&gt;                   \
-    -hda &lt;disk&gt;                    \
-    -device qemu-xhci,id=xhci      \
-    -device usb-host,bus=xhci.0,vendorid=0x05e1,productid=0x0408,id=capture-card
+<p><strong>Note</strong>: <code>-a</code> <em>ands</em> the results. If <code>-a</code> is not given all open files matching
+<code>$USER</code> and all tcp connections are listed (<em>ored</em>).</p>
+<h2 id="open-connection-to-specific-host"><a class="header" href="#open-connection-to-specific-host">Open connection to specific host</a></h2>
+<p>Show open connections to <code>localhost</code> for <code>$USER</code>:</p>
+<pre><code class="language-markdown">lsof -a -u $USER -i @localhost
 </code></pre>
-<h3 id="cpu--ram"><a class="header" href="#cpu--ram">CPU &amp; RAM</a></h3>
-<pre><code class="language-bash"># Emulate host CPU in guest VM, enabling all supported host featured (requires KVM).
-# List available CPUs `qemu-system-x86_64 -cpu help`.
--cpu host
-
-# Enable KVM instead software emulation.
--enable-kvm
-
-# Configure number of guest CPUs.
--smp &lt;N&gt;
-
-# Configure size of guest RAM.
--m 8G
+<h2 id="open-connection-to-specific-port"><a class="header" href="#open-connection-to-specific-port">Open connection to specific port</a></h2>
+<p>Show open connections to port <code>:1234</code> for <code>$USER</code>:</p>
+<pre><code class="language-markdown">lsof -a -u $USER -i :1234
 </code></pre>
-<h3 id="graphic--display"><a class="header" href="#graphic--display">Graphic &amp; Display</a></h3>
-<pre><code class="language-bash"># Use sdl window as display and enable openGL context.
--display sdl,gl=on
-
-# Use vnc server as display (eg on display `:42` here).
--display vnc=localhost:42
-
-# Confifure virtio as 3D video graphic accelerator (requires virgl in guest).
--vga virtio
+<h2 id="ipv4-tcp-connections-in-established-state"><a class="header" href="#ipv4-tcp-connections-in-established-state">IPv4 TCP connections in <code>ESTABLISHED</code> state</a></h2>
+<pre><code class="language-markdown">lsof -i 4TCP -s TCP:ESTABLISHED
 </code></pre>
-<h3 id="boot-menu"><a class="header" href="#boot-menu">Boot Menu</a></h3>
-<pre><code class="language-bash"># Enables boot menu to select boot device (enter with `ESC`).
--boot menu=on
+<h2 id="list-open-files-in-a-mounted-directory"><a class="header" href="#list-open-files-in-a-mounted-directory">List open files in a mounted directory.</a></h2>
+<p>This may help to find which processes keep devices busy when trying to unmount
+and the device is currently busy.</p>
+<pre><code class="language-markdown"># Assuming /proc is a mount point.
+lsof /proc
 </code></pre>
-<h3 id="block-devices"><a class="header" href="#block-devices">Block devices</a></h3>
-<pre><code class="language-bash"># Attach cdrom drive with iso to a VM.
--cdrom &lt;iso&gt;
-
-# Attach disk drive to a VM.
--hda &lt;disk&gt;
-
-# Generic way to configure &amp; attach a drive to a VM.
--drive file=&lt;file&gt;,format=qcow2
+<div style="break-before: page; page-break-before: always;"></div><h1 id="pidstat1"><a class="header" href="#pidstat1">pidstat(1)</a></h1>
+<pre><code class="language-markdown">pidstat [opt] [interval] [cont]
+  -U [user]     show username instead UID, optionally only show for user
+  -r            memory statistics
+  -d            I/O statistics
+  -h            single line per process and no lines with average
 </code></pre>
-<h4 id="create-a-disk-with-qemu-img"><a class="header" href="#create-a-disk-with-qemu-img">Create a disk with <a href="https://qemu-project.gitlab.io/qemu/tools/qemu-img.html"><code>qemu-img</code></a></a></h4>
-<p>To create a <code>qcow2</code> disk (qemu copy-on-write) of size <code>10G</code>:</p>
-<pre><code class="language-bash">qemu-img create -f qcow2 disk.qcow2 10G
+<h1 id="page-fault-and-memory-utilization"><a class="header" href="#page-fault-and-memory-utilization">Page fault and memory utilization</a></h1>
+<pre><code class="language-markdown">pidstat -r -p &lt;pid&gt; [interval] [count]
 </code></pre>
-<p>The disk does not contain any <code>partitions</code> or a <code>partition table</code>.
-We can format the disk from <strong>within the <strong>guest</strong></strong> as following example:</p>
-<pre><code class="language-bash"># Create `gpt` partition table.
-sudo parted /dev/sda mktable gpt
-
-# Create two equally sized primary partitions.
-sudo parted /dev/sda mkpart primary 0% 50%
-sudo parted /dev/sda mkpart primary 50% 100%
-
-# Create filesystem on each partition.
-sudo mkfs.ext3 /dev/sda1
-sudo mkfs.ext4 /dev/sda2
+<pre><code class="language-markdown">minor_pagefault: Happens when the page needed is already in memory but not
+                 allocated to the faulting process, in that case the kernel
+                 only has to create a new page-table entry pointing to the
+                 shared physical page (not required to load a memory page from
+                 disk).
 
-lsblk -f /dev/sda
-  NAME   FSTYPE LABEL UUID FSAVAIL FSUSE% MOUNTPOINT
-  sda
-  ├─sda1 ext3         ....
-  └─sda2 ext4         ....
+major_pagefault: Happens when the page needed is NOT in memory, the kernel
+                 has to create a new page-table entry and populate the
+                 physical page (required to load a memory page from disk).
 </code></pre>
-<h3 id="usb"><a class="header" href="#usb">USB</a></h3>
-<h4 id="host-controller"><a class="header" href="#host-controller">Host Controller</a></h4>
-<pre><code class="language-bash"># Add XHCI USB controller to the VM (supports USB 3.0, 2.0, 1.1).
-# `id=xhci` creates a usb bus named `xhci`.
--device qemu-xhci,id=xhci
+<h1 id="io-statistics"><a class="header" href="#io-statistics">I/O statistics</a></h1>
+<pre><code class="language-markdown">pidstat -d -p &lt;pid&gt; [interval] [count]
 </code></pre>
-<h4 id="usb-device"><a class="header" href="#usb-device">USB Device</a></h4>
-<pre><code class="language-bash"># Pass-through USB device from host identified by vendorid &amp; productid and
-# attach to usb bus `xhci.0` (defined with controller `id`).
--device usb-host,bus=xhci.0,vendorid=0x05e1,productid=0x0408
+<div style="break-before: page; page-break-before: always;"></div><h1 id="pgrep1"><a class="header" href="#pgrep1">pgrep(1)</a></h1>
+<pre><code class="language-markdown">pgrep [opts] &lt;pattern&gt;
+  -n         only list newest matching process
+  -u &lt;usr&gt;   only show matching for user &lt;usr&gt;
+  -l         additionally list command
+  -a         additionally list command + arguments
+  -x         match exactly
 </code></pre>
-<h2 id="debugging"><a class="header" href="#debugging">Debugging</a></h2>
-<pre><code class="language-bash"># Open gdbstub on tcp `&lt;port&gt;` (`-s` shorthand for `-gdb tcp::1234`).
--gdb tcp::&lt;port&gt;
-
-# Freeze guest CPU at startup and wait for debugger connection.
--S
+<h2 id="debug-newest-process"><a class="header" href="#debug-newest-process">Debug newest process</a></h2>
+<p>For example attach gdb to newest zsh process from <code>$USER</code>.</p>
+<pre><code class="language-markdown">gdb -p $(pgrep -n -u $USER zsh)
 </code></pre>
-<h2 id="io-redirection-2"><a class="header" href="#io-redirection-2">IO redirection</a></h2>
-<pre><code class="language-bash"># Create raw tcp server for `serial IO` and wait until a client connects
-# before executing the guest.
--serial tcp:localhost:12345,server,wait
-
-# Create telnet server for `serial IO` and wait until a client connects
-# before executing the guest.
--serial telnet:localhost:12345,server,wait
-
-# Configure redirection for the QEMU `mointor`, arguments similar to `-serial`
-# above.
--monitor ...
+<div style="break-before: page; page-break-before: always;"></div><h1 id="ps1"><a class="header" href="#ps1">ps(1)</a></h1>
+<pre><code>ps [opt]
+  opt:
+    --no-header .... do not print column header
+    -o &lt;OUT&gt; ....... comma separated list of output columns
+    -p &lt;PID&gt; ....... only show pid
+    -C &lt;name&gt; ...... only show processes matching name
+    -T ............. list threads
+    --signames ..... use short signames instead bitmasks
 </code></pre>
 <blockquote>
-<p>In <code>server</code> mode use <code>nowait</code> to execute guest without waiting for a client
-connection.</p>
+<p>Set <code>PS_FORMAT</code> env variable to setup default output columns.</p>
 </blockquote>
-<h2 id="network"><a class="header" href="#network">Network</a></h2>
-<pre><code class="language-bash"># Redirect host tcp port `1234` to guest port `4321`.
--nic user,hostfwd=tcp:localhost:1234-:4321
-</code></pre>
-<h2 id="shared-drives"><a class="header" href="#shared-drives">Shared drives</a></h2>
-<pre><code class="language-bash"># Attach a `virtio-9p-pci` device to the VM.
-# The guest requires 9p support and can mount the shared drive as:
-#   mount -t 9p -o trans=virtio someName /mnt
--virtfs local,id=someName,path=&lt;someHostPath&gt;,mount_tag=someName,security_model=none
-</code></pre>
-<h2 id="debug-logging"><a class="header" href="#debug-logging">Debug logging</a></h2>
-<pre><code class="language-bash"># List debug items.
--d help
-
-# Write debug log to file instead stderr.
--D &lt;file&gt;
+<p>Frequently used output columns</p>
+<pre><code>pid        process id
+ppid       parent process id
+pgid       process group id
+tid        thread id
 
-# Examples
--d in_asm       Log executed guest instructions.
-</code></pre>
-<h2 id="tracing"><a class="header" href="#tracing">Tracing</a></h2>
-<pre><code class="language-bash"># List name of all trace points.
--trace help
+comm       name of process
+cmd        name of process + args (full)
 
-# Enable trace points matching pattern and optionally write trace to file.
--trace &lt;pattern&gt;[,file=&lt;file&gt;]
+etime      elapsed time (since process started)
+user       user owning process
+thcount    thread count of process
+nice       nice value (-20 highest priority to 19 lowest)
 
-# Enable trace points for all events listed in the &lt;events&gt; file.
-# File must contain one event/pattern per line.
--trace events=&lt;events&gt;
-</code></pre>
-<h2 id="vm-snapshots"><a class="header" href="#vm-snapshots">VM snapshots</a></h2>
-<p>VM snapshots require that there is at least on <code>qcow2</code> disk attached to the VM
-(<a href="https://qemu-project.gitlab.io/qemu/system/images.html#vm-005fsnapshots">VM Snapshots</a>).</p>
-<p>Commands for qemu <a href="https://qemu-project.gitlab.io/qemu/system/monitor.html">Monitor</a> or <a href="https://qemu-project.gitlab.io/qemu/interop/qemu-qmp-ref.html">QMP</a>:</p>
-<pre><code class="language-bash"># List available snapshots.
-info snapshots
+pcpu       cpu utilization (percent)
+pmem       physical resident set (rss) (percent)
+rss        physical memory (in kb)
+vsz        virtual memory (in kb)
 
-# Create/Load/Delete snapshot with name &lt;tag&gt;.
-savevm &lt;tag&gt;
-loadvm &lt;tag&gt;
-delvm &lt;tag&gt;
+sig        mask of pending signals
+sigcatch   mask of caught signals
+sigignore  mask of ignored signals
+sigmask    mask of blocked signals
 </code></pre>
-<p>The snapshot can also be directly specified when invoking qemu as:</p>
-<pre><code class="language-bash">qemu-system-x86_64 \
-    -loadvm &lt;tag&gt;  \
-    ...
+<h2 id="example-use-output-for-scripting"><a class="header" href="#example-use-output-for-scripting">Example: Use output for scripting</a></h2>
+<pre><code class="language-sh">for tid in $(ps -o tid --no-header -T -p 31084); do
+    taskset -c -p $tid;
+done
 </code></pre>
-<h2 id="vm-migration"><a class="header" href="#vm-migration">VM Migration</a></h2>
-<p><code>Online</code> migration example:</p>
-<pre><code class="language-bash"># Start machine 1 on host ABC.
-qemu-system-x86_64 -monitor stdio -cdrom &lt;iso&gt;
-
-# Prepare machine 2 on host DEF as migration target.
-# Listen for any connection on port 12345.
-qemu-system-x86_64 -monitor stdio -incoming tcp:0.0.0.0:12345
-
-# Start migration from the machine 1 monitor console.
-(qemu) migrate tcp:DEF:12345
+<h2 id="example-watch-processes-by-name"><a class="header" href="#example-watch-processes-by-name">Example: Watch processes by name</a></h2>
+<pre><code class="language-sh">watch -n1 ps -o pid,pcpu,pmem,rss,vsz,state,user,comm -C fish
 </code></pre>
-<p>Save to external file example:</p>
-<pre><code class="language-bash">```bash
-# Start machine 1.
-qemu-system-x86_64 -monitor stdio -cdrom &lt;iso&gt;
-
-# Save VM state to file.
-(qemu) migrate "exec:gzip -c &gt; vm.gz"
+<h2 id="example-show-signal-information"><a class="header" href="#example-show-signal-information">Example: Show signal information</a></h2>
+<pre><code class="language-sh"># With signal masks.
+ps -o pid,user,sig,sigcatch,sigignore,sigmask,comm -p 66570
 
-# Load VM from file.
-qemu-system-x86_64 -monitor stdio -incoming "exec: gzip -d -c vm.gz"
-</code></pre>
-<blockquote>
-<p>The migration source machine and the migration target machine should be
-launched with the <strong>same</strong> parameters.</p>
-</blockquote>
-<h2 id="appendix-direct-kernel-boot"><a class="header" href="#appendix-direct-kernel-boot">Appendix: Direct <code>Kernel</code> boot</a></h2>
-<p>Example command line to directly boot a <code>Kernel</code> with an <code>initrd</code> ramdisk.</p>
-<pre><code class="language-bash">qemu-system-x86_64                                                     \
-    -cpu host                                                          \
-    -enable-kvm                                                        \
-    -kernel &lt;dir&gt;/arch/x86/boot/bzImage                                \
-    -append "earlyprintk=ttyS0 console=ttyS0 nokaslr init=/init debug" \
-    -initrd &lt;dir&gt;/initramfs.cpio.gz                                    \
-    ...
+# With signal names.
+ps --signames -o pid,user,sig,sigcatch,sigignore,sigmask,comm -p 66570
 </code></pre>
-<p>Instructions to build a minimal <a href="https://blog.memzero.de/kernel-debugging-qemu"><code>Kernel</code> and <code>initrd</code></a>.</p>
-<h2 id="appendix-cheap-instruction-tracer"><a class="header" href="#appendix-cheap-instruction-tracer">Appendix: Cheap instruction tracer</a></h2>
-<pre><code class="language-make">test: test.s
-	as -o test.o test.s
-	ld -o test test.o testc.o
-
-trace: test
-	qemu-x86_64 -singlestep -d nochain,cpu ./test 2&gt;&amp;1 | awk '/RIP/ { print $$1; }'
-
-clean:
-	$(RM) test test-bin test.o
+<div style="break-before: page; page-break-before: always;"></div><h1 id="pmap1"><a class="header" href="#pmap1">pmap(1)</a></h1>
+<pre><code class="language-markdown">pmap [opts] &lt;pid&gt;
+    Dump virtual memory map of process.
+    Compared to /proc/&lt;pid&gt;/maps it shows the size of the mappings.
+opts:
+  -p         show full path in the mapping
+  -x         show details (eg RSS usage of each segment)
 </code></pre>
-<pre><code class="language-x86asm">.section .text, "ax"
-
-.global _start
-_start:
-    xor %rax, %rax
-    mov $0x8, %rax
-1:
-    cmp $0, %rax
-    je 2f
-    dec %rax
-    jmp 1b
-2:
-    # x86-64 exit(2) syscall
-    mov $0, %rdi
-    mov $60, %rax
-    syscall
+<div style="break-before: page; page-break-before: always;"></div><h1 id="pstack1"><a class="header" href="#pstack1">pstack(1)</a></h1>
+<pre><code class="language-markdown">pstack &lt;pid&gt;
+    Dump stack for all threads of process.
 </code></pre>
-<h2 id="references"><a class="header" href="#references">References</a></h2>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="trace-and-profile"><a class="header" href="#trace-and-profile">Trace and Profile</a></h1>
 <ul>
-<li><a href="https://github.com/qemu/qemu/blob/master/docs/usb2.txt">QEMU USB</a></li>
-<li><a href="https://qemu-project.gitlab.io/qemu/tools/qemu-img.html">QEMU IMG</a></li>
-<li><a href="https://qemu-project.gitlab.io/qemu/tools/index.html">QEMU Tools</a></li>
-<li><a href="https://qemu-project.gitlab.io/qemu/system/index.html">QEMU System</a></li>
-<li><a href="https://qemu-project.gitlab.io/qemu/system/invocation.html">QEMU Invocation (command line args)</a></li>
-<li><a href="https://qemu-project.gitlab.io/qemu/system/monitor.html">QEMU Monitor</a></li>
-<li><a href="https://qemu-project.gitlab.io/qemu/interop/qemu-qmp-ref.html">QEMU machine protocol (QMP)</a></li>
-<li><a href="https://qemu-project.gitlab.io/qemu/system/images.html#vm-005fsnapshots">QEMU VM Snapshots</a></li>
+<li><a href="trace_profile/./time.html">time</a></li>
+<li><a href="trace_profile/./strace.html">strace</a></li>
+<li><a href="trace_profile/./ltrace.html">ltrace</a></li>
+<li><a href="trace_profile/./perf.html">perf</a></li>
+<li><a href="trace_profile/./oprofile.html">OProfile</a></li>
+<li><a href="trace_profile/./callgrind.html">callgrind</a></li>
 </ul>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="pacman1"><a class="header" href="#pacman1">pacman(1)</a></h1>
-<h2 id="remote-package-repositories"><a class="header" href="#remote-package-repositories">Remote package repositories</a></h2>
-<pre><code class="language-text">pacman -Sy              refresh package database
-pacman -S &lt;pkg&gt;         install pkg
-pacman -Ss &lt;regex&gt;      search remote package database
-pacman -Si &lt;pkg&gt;        get info for pkg
-pacman -Su              upgrade installed packages
-pacman -Sc              clean local package cache
+<div style="break-before: page; page-break-before: always;"></div><h1 id="usrbintime1"><a class="header" href="#usrbintime1">/usr/bin/time(1)</a></h1>
+<pre><code class="language-markdown"># statistics of process run
+/usr/bin/time -v &lt;cmd&gt;
 </code></pre>
-<h2 id="remove-packages"><a class="header" href="#remove-packages">Remove packages</a></h2>
-<pre><code class="language-text">pacman -Rsn &lt;pkg&gt;               uninstall package and unneeded deps + config files
+<div style="break-before: page; page-break-before: always;"></div><h1 id="strace1"><a class="header" href="#strace1">strace(1)</a></h1>
+<pre><code class="language-markdown">strace [opts] [prg]
+  -f .......... follow child processes on fork(2)
+  -ff ......... follow fork and separate output file per child
+  -p &lt;pid&gt; .... attach to running process
+  -s &lt;size&gt; ... max string size, truncate of longer (default: 32)
+  -e &lt;expr&gt; ... expression for trace filtering
+  -o &lt;file&gt; ... log output into &lt;file&gt;
+  -c .......... dump syscall statitics at the end
+  -C .......... like -c but dump regular ouput as well
+  -k .......... dump stack trace for each syscall
+  -P &lt;path&gt; ... only trace syscall accesing path
+  -y .......... print paths for FDs
+  -tt ......... print absolute timestamp (with us precision)
+  -r .......... print relative timestamp
+  -z .......... log only successful syscalls
+  -Z .......... log only failed syscalls
+  -n .......... print syscall numbers
+  -y .......... translate fds (eg file path, socket)
+  -yy ......... translate fds with all information (eg IP)
+  -x .......... print non-ASCII chars as hex string
 </code></pre>
-<h2 id="local-package-database"><a class="header" href="#local-package-database">Local package database</a></h2>
-<p>Local package database of installed packages.</p>
-<pre><code class="language-text">pacman -Q               list all installed packages
-pacman -Qs &lt;regex&gt;      search local package database
-pacman -Ql &lt;pkg&gt;        list files installed by pkg
-pacman -Qo &lt;file&gt;       query package that owns file
-pacman -Qe              only list explicitly installed packages
+<pre><code class="language-markdown">&lt;expr&gt;:
+  trace=syscall[,syscall] .... trace only syscall listed
+  trace=file ................. trace all syscall that take a filename as arg
+  trace=process .............. trace process management related syscalls
+  trace=signal ............... trace signal related syscalls
+  signal ..................... trace signals delivered to the process
 </code></pre>
-<h2 id="local-file-database"><a class="header" href="#local-file-database">Local file database</a></h2>
-<p>Local file database which allows to search packages owning certain files.
-Also searches non installed packages, but database must be synced.</p>
-<pre><code class="language-text">pacman -Fy              refresh file database
-pacman -Fl &lt;pkg&gt;        list files in pkg (must not be installed)
-pacman -Fx &lt;regex&gt;      search 
+<h1 id="examples-8"><a class="header" href="#examples-8">Examples</a></h1>
+<p>Trace <code>open(2)</code> &amp; <code>socket(2)</code> syscalls for a running process + child processes:</p>
+<pre><code class="language-markdown">strace -f -e trace=open,socket -p &lt;pid&gt;
 </code></pre>
-<h2 id="hacks"><a class="header" href="#hacks">Hacks</a></h2>
-<p>Uninstall all orphaned packages (including config files) that were installed as
-dependencies.</p>
-<pre><code class="language-text">pacman -Rsn $(pacman -Qtdq)
+<p>Trace signals delivered to a running process:</p>
+<pre><code class="language-markdown">strace -e signal -e 'trace=!all' -p &lt;pid&gt;
 </code></pre>
-<p>List explicitly installed packages that are not required as dependency by any
-package and sort by size.</p>
-<pre><code class="language-text">pacman -Qetq | xargs pacman -Qi |
-    awk '/Name/ { name=$3 }
-         /Installed Size/ { printf "%8.2f%s %s\n", $4, $5, name }' |
-    sort -h
-</code></pre>
-<p>Install package into different <code>root</code> directory but keep using the default
-database.</p>
-<pre><code class="language-text">pacman --root abc --dbpath /var/lib/pacman -S mingw-w64-gcc
+<div style="break-before: page; page-break-before: always;"></div><h1 id="ltrace1"><a class="header" href="#ltrace1">ltrace(1)</a></h1>
+<pre><code class="language-markdown">ltrace [opts] [prg]
+  -f .......... follow child processes on fork(2)
+  -p &lt;pid&gt; .... attach to running process
+  -o &lt;file&gt; ... log output into &lt;file&gt;
+  -l &lt;filter&gt; . show who calls into lib matched by &lt;filter&gt;
+  -C .......... demangle
 </code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="dot1"><a class="header" href="#dot1">dot(1)</a></h1>
-<p><a href="https://edotor.net/">Online playground</a></p>
-<h2 id="example-dot-file-to-copy--paste-from"><a class="header" href="#example-dot-file-to-copy--paste-from">Example <code>dot</code> file to copy &amp; paste from.</a></h2>
-<p>Can be rendered to <code>svg</code> with the following command.</p>
-<pre><code class="language-bash">dot -T svg -o g.svg g.dot
+<h1 id="example-4"><a class="header" href="#example-4">Example</a></h1>
+<p>List which program/libs call into <code>libstdc++</code>:</p>
+<pre><code class="language-bash">ltrace -l '*libstdc++*' -C -o ltrace.log ./main
 </code></pre>
-<p>Example <code>dot</code> file.</p>
-<pre><code class="language-dot">// file: g.dot
-digraph {
-    // Render ranks from left to right.
-    rankdir=LR
-    // Make background transparent.
-    bgcolor=transparent
-
-    // Global node attributes.
-    node [shape=box]
-    // Global edge attributes.
-    edge [style=dotted,color=red]
+<div style="break-before: page; page-break-before: always;"></div><h1 id="perf1"><a class="header" href="#perf1">perf(1)</a></h1>
+<pre><code>perf list     show supported hw/sw events &amp; metrics
+  -v ........ print longer event descriptions
+  --details . print information on the perf event names
+              and expressions used internally by events
 
-    // Add nodes &amp; edge.
-    stage1 -&gt; stage2
-    // Add multiple edges at once.
-    stage2 -&gt; { stage3_1, stage3_2 }
-    // Add edge with custom attributes.
-    stage3_2 -&gt; stage4 [label="some text"]
+perf stat
+  -p &lt;pid&gt; ..... show stats for running process
+  -o &lt;file&gt; .... write output to file (default stderr)
+  -I &lt;ms&gt; ...... show stats periodically over interval &lt;ms&gt;
+  -e &lt;ev&gt; ...... select event(s)
+  -M &lt;met&gt; ..... print metric(s), this adds the metric events
+  --all-user ... configure all selected events for user space
+  --all-kernel . configure all selected events for kernel space
 
-    // Set custom attributes for specific node.
-    stage4 [color=green,fillcolor=lightgray,style="filled,dashed",label="s4"]
+perf top
+  -p &lt;pid&gt; .. show stats for running process
+  -F &lt;hz&gt; ... sampling frequency
+  -K ........ hide kernel threads
 
-    // Create a subgraph. This can be used to group nodes/edges or as scope for
-    // global node/edge attributes.
-    // If the name starts with 'cluster' a border is drawn.
-    subgraph cluster_1 {
-        stage5_1
-        stage5_2
-    }
+perf record
+  -p &lt;pid&gt; ............... record stats for running process
+  -o &lt;file&gt; .............. write output to file (default perf.data)
+  -F &lt;hz&gt; ................ sampling frequency
+  --call-graph &lt;method&gt; .. [fp, dwarf, lbr] method how to caputre backtrace
+                           fp   : use frame-pointer, need to compile with
+                                  -fno-omit-frame-pointer
+                           dwarf: use .cfi debug information
+                           lbr  : use hardware last branch record facility
+  -g ..................... short-hand for --call-graph fp
+  -e &lt;ev&gt; ................ select event(s)
+  --all-user ............. configure all selected events for user space
+  --all-kernel ........... configure all selected events for kernel space
+  -M intel ............... use intel disassembly in annotate
 
-    // Add some edges to subgraph nodes.
-    stage3_1 -&gt; { stage5_1, stage5_2 }
-}
+perf report
+  -n .................... annotate symbols with nr of samples
+  --stdio ............... report to stdio, if not presen tui mode
+  -g graph,0.5,callee ... show callee based call chains with value &gt;0.5
 </code></pre>
-<p>Rendered <code>svg</code> file.
-<img src="tools/assets/g.svg" alt="g.svg" /></p>
-<h2 id="references-1"><a class="header" href="#references-1">References</a></h2>
-<ul>
-<li><a href="https://graphviz.org/doc/info/lang.html">DOT language</a></li>
-<li><a href="https://graphviz.org/doc/info/attrs.html">Attributes</a></li>
-<li><a href="https://graphviz.org/doc/info/shapes.html">Node shapes</a></li>
-<li><a href="https://graphviz.org/doc/info/colors.html">Colors</a></li>
-<li><a href="https://graphviz.org/pdf/dotguide.pdf">User manual</a></li>
-</ul>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="ffmpeg-1"><a class="header" href="#ffmpeg-1">ffmpeg (1)</a></h1>
-<h2 id="screen-capture-specific-window-x11"><a class="header" href="#screen-capture-specific-window-x11">screen capture specific window (x11)</a></h2>
-<p>Following snippet allows to select a window which is then captured.</p>
-<pre><code class="language-bash">#!/bin/bash
-
-echo "Click on window to record .."
-# Extract window size and x,y offset.
-video_args=$(xwininfo \
-    | awk '/Absolute upper-left X:/ { xoff = $4 }
-           /Absolute upper-left Y:/ { yoff=$4 }
-           /Width:/ { if ($2 % 2 == 1) { width=$2-1; } else { width=$2; } }
-           /Height:/ { if ($2 % 2 == 1) { height=$2-1; } else { height=$2; } }
-           END { printf "-video_size %dx%d -i :0.0+%d,%d", width, height, xoff, yoff  }')
+<pre><code>Useful &lt;ev&gt;:
+  page-faults
+  minor-faults
+  major-faults
+  cpu-cycles`
+  task-clock
+</code></pre>
+<h2 id="select-specific-events"><a class="header" href="#select-specific-events">Select specific events</a></h2>
+<p>Events to sample are specified with the <code>-e</code> option, either pass a comma
+separated list or pass <code>-e</code> multiple times.</p>
+<p>Events are specified in the following form <code>name[:modifier]</code>. The list and
+description of the <code>modifier</code> can be found in the
+<a href="https://man7.org/linux/man-pages/man1/perf-list.1.html"><code>perf-list(1)</code></a> manpage under <code>EVENT MODIFIERS</code>.</p>
+<pre><code class="language-sh"># L1 i$ misses in user space
+# L2 i$ stats in user/kernel space mixed
+# Sample specified events.
+perf stat -e L1-icache-load-misses:u \
+          -e l2_rqsts.all_code_rd:uk,l2_rqsts.code_rd_hit:k,l2_rqsts.code_rd_miss:k \
+          -- stress -c 2
+</code></pre>
+<p>The <code>--all-user</code> and <code>--all-kernel</code> options append a <code>:u</code> and <code>:k</code> modifier to
+all specified events. Therefore the following two command lines are equivalent.</p>
+<pre><code class="language-sh"># 1)
+perf stat -e cycles:u,instructions:u -- ls
 
-ffmpeg -framerate 25 -f x11grab $video_args -pix_fmt yuv420p $@ output.mp4
+# 2)
+perf stat --all-user -e cycles,instructions -- ls
+</code></pre>
+<h3 id="raw-events"><a class="header" href="#raw-events">Raw events</a></h3>
+<p>In case perf does not provide a <em>symbolic</em> name for an event, the event can be
+specified in a <em>raw</em> form as <code>r + UMask + EventCode</code>.</p>
+<p>The following is an example for the <a href="https://github.com/intel/perfmon/blob/09c155f72e1b8f14b09aea346a35467a03a7d62b/SNB/events/sandybridge_core.json#L808">L2_RQSTS.CODE_RD_HIT</a> event
+with <code>EventCode=0x24</code> and <code>UMask=0x10</code> on my laptop with a <code>sandybridge</code> uarch.</p>
+<pre><code class="language-sh">perf stat -e l2_rqsts.code_rd_hit -e r1024 -- ls
+# Performance counter stats for 'ls':
+#
+#       33.942      l2_rqsts.code_rd_hit
+#       33.942      r1024
+</code></pre>
+<h3 id="find-raw-performance-counter-events-intel"><a class="header" href="#find-raw-performance-counter-events-intel">Find raw performance counter events (intel)</a></h3>
+<p>The <a href="https://github.com/intel/perfmon"><code>intel/perfmon</code></a> repository provides a performance event
+databases for the different intel uarchs.</p>
+<p>The table in <a href="https://github.com/intel/perfmon/blob/main/mapfile.csv"><code>mapfile.csv</code></a> can be used to lookup the
+corresponding uarch, just grab the family model from the procfs.</p>
+<pre><code class="language-sh"> cat /proc/cpuinfo | awk '/^vendor_id/  { V=$3 }
+                          /^cpu family/ { F=$4 }
+                          /^model\s*:/  { printf "%s-%d-%x\n",V,F,$3 }'
 </code></pre>
 <blockquote>
-<p>Use <code>yuv420p</code> pixel format if video is played on the web
-(<a href="https://stackoverflow.com/questions/32829514/which-pixel-format-for-web-mp4-video">ref</a>)</p>
+<p>The table in <a href="https://github.com/intel/perfmon/tree/main#performance-monitoring-events">performance monitoring events</a> describes how
+events are sorted into the different files.</p>
 </blockquote>
-<p>The input <code>-i 0,0+xoff,yoff</code> means to capture <code>$DISPLAY=0.0</code> starting at the
-coordinate <code>(xoff, yoff)</code>, which is the left-upper corner, and the size of the
-capture is defined by the <code>-video_size</code> argument.</p>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="column1"><a class="header" href="#column1">column(1)</a></h1>
-<h2 id="examples-4"><a class="header" href="#examples-4">Examples</a></h2>
-<pre><code class="language-sh"># Show as table (aligned columns), with comma as delimiter from stdin.
-echo -e 'a,b,c\n111,22222,33' | column -t -s ','
+<h3 id="raw-events-for-perfs-own-symbolic-names"><a class="header" href="#raw-events-for-perfs-own-symbolic-names">Raw events for perfs own symbolic names</a></h3>
+<p>Perf also defines some own <em>symbolic</em> names for events. An example is the
+<code>cache-references</code> event. The <a href="https://man7.org/linux/man-pages/man2/perf_event_open.2.html"><code>perf_event_open(2)</code></a> manpage
+gives the following description.</p>
+<pre><code class="language-man">perf_event_open(2)
 
-# Show file as table.
-column -t -s ',' test.csv
+PERF_COUNT_HW_CACHE_REFERENCES
+    Cache accesses.  Usually this indicates Last Level Cache accesses but this
+    may vary depending on your CPU.  This may include prefetches and coherency
+    messages; again this depends on the design of your CPU.
 </code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="sort1"><a class="header" href="#sort1">sort(1)</a></h1>
-<pre><code>sort [opts] [file]
-  opts:
-    -r      reverse output
-    -b      ignore leading blanks
-
-    -n      sort by numeric
-    -h      sort by human numeric
-    -V      sort by version
-
-    -k&lt;N&gt;  sort by Nth key
-    -t&lt;S&gt;  field separator
+<p>The <code>sysfs</code> can be consulted to get the concrete performance counter on the
+given system.</p>
+<pre><code class="language-sh">cat /sys/devices/cpu/events/cache-misses
+# event=0x2e,umask=0x41
 </code></pre>
-<h2 id="examples-5"><a class="header" href="#examples-5">Examples</a></h2>
-<pre><code class="language-sh"># Sort by directory sizes.
-du -sh * | sort -h
+<h2 id="flamegraph"><a class="header" href="#flamegraph"><a href="https://github.com/brendangregg/FlameGraph"><code>Flamegraph</code></a></a></h2>
+<h3 id="flamegraph-with-single-event-trace"><a class="header" href="#flamegraph-with-single-event-trace">Flamegraph with single event trace</a></h3>
+<pre><code>perf record -g -e cpu-cycles -p &lt;pid&gt;
+perf script | FlameGraph/stackcollapse-perf.pl | FlameGraph/flamegraph.pl &gt; cycles-flamegraph.svg
 </code></pre>
-<pre><code class="language-sh"># Sort numeric by second key.
-# The default key separator is non-blank to blank transition.
-echo 'a 4
-d 10
-c 21' | sort -k2 -n
-
-# Sort numeric by second key, split at comma.
-echo 'a,4
-d,10
-c,21' | sort -k2 -n -t,
+<h3 id="flamegraph-with-multiple-event-traces"><a class="header" href="#flamegraph-with-multiple-event-traces">Flamegraph with multiple event traces</a></h3>
+<pre><code class="language-sh">perf record -g -e cpu-cycles,page-faults -p &lt;pid&gt;
+perf script --per-event-dump
+# fold &amp; generate as above
 </code></pre>
-<blockquote>
-<p>Use <code>--debug</code> to annotate part of the line used to sort and hence debug the key usage.</p>
-</blockquote>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="sed1"><a class="header" href="#sed1">sed(1)</a></h1>
-<pre><code>sed [opts] [script] [file]
-  opts:
-    -i          edit file in place
-    -i.bk       edit file in place and create backup file
-                (with .bk suffix, can be specified differently)
-    --follow-symlinks
-                follow symlinks when editing in place
-    -e SCRIPT   add SCRIPT to commands to be executed
-                (can be specified multiple times)
-    -f FILE     add content of FILE to command to be executed
+<h2 id="examples-9"><a class="header" href="#examples-9">Examples</a></h2>
+<h3 id="estimate-max-instructions-per-cycle"><a class="header" href="#estimate-max-instructions-per-cycle">Estimate max instructions per cycle</a></h3>
+<pre><code class="language-c">#define NOP4        "nop\nnop\nnop\nnop\n"
+#define NOP32       NOP4   NOP4   NOP4   NOP4   NOP4   NOP4   NOP4   NOP4
+#define NOP256      NOP32  NOP32  NOP32  NOP32  NOP32  NOP32  NOP32  NOP32
+#define NOP2048     NOP256 NOP256 NOP256 NOP256 NOP256 NOP256 NOP256 NOP256
 
-    --debug     annotate program execution
+int main() {
+  for (unsigned i = 0; i &lt; 2000000; ++i) {
+    asm volatile(NOP2048);
+  }
+}
 </code></pre>
-<h2 id="examples-6"><a class="header" href="#examples-6">Examples</a></h2>
-<h3 id="delete-lines"><a class="header" href="#delete-lines">Delete lines</a></h3>
-<pre><code class="language-sh"># Delete two lines.
-echo -e 'aa\nbb\ncc\ndd' | sed '1d;3d'
-# bb
-# dd
+<pre><code class="language-sh">perf stat -e cycles,instructions ./noploop
+# Performance counter stats for './noploop':
+#
+#     1.031.075.940      cycles
+#     4.103.534.341      instructions       #    3,98  insn per cycle
+</code></pre>
+<h3 id="caller-vs-callee-callstacks"><a class="header" href="#caller-vs-callee-callstacks">Caller vs callee callstacks</a></h3>
+<p>The following gives an example for a scenario where we have the following calls</p>
+<ul>
+<li><code>main -&gt; do_foo() -&gt; do_work()</code></li>
+<li><code>main -&gt; do_bar() -&gt; do_work()</code></li>
+</ul>
+<pre><code class="language-sh">perf report --stdio -g graph,callee
 
-# Delete last ($) line.
-echo -e 'aa\nbb\ncc\ndd' | sed '$d'
-# aa
-# bb
-# cc
-
-# Delete range of lines.
-echo -e 'aa\nbb\ncc\ndd' | sed '1,3d'
-# dd
+# Children      Self  Command  Shared Object         Symbols
+# ........  ........  .......  ....................  .................
+#
+#  49.71%    49.66%   bench    bench                 [.] do_work
+#          |
+#           --49.66%--_start                &lt;- callstack bottom
+#                     __libc_start_main
+#                     0x7ff366c62ccf
+#                     main
+#                     |
+#                     |--25.13%--do_bar
+#                     |          do_work    &lt;- callstack top
+#                     |
+#                      --24.53%--do_foo
+#                                do_work
 
-# Delete lines matching pattern.
-echo -e 'aa\nbb\ncc\ndd' | sed '/bb/d'
-# aa
-# cc
-# dd
+perf report --stdio -g graph,callee
 
-# Delete lines NOT matching pattern.
-echo -e 'aa\nbb\ncc\ndd' | sed '/bb/!d'
-# bb
+# Children      Self  Command  Shared Object         Symbols
+# ........  ........  .......  ....................  .................
+#
+#  49.71%    49.66%   bench    bench                 [.] do_work
+#          |
+#          ---do_work                       &lt;- callstack top
+#             |
+#             |--25.15%--do_bar
+#             |          main
+#             |          0x7ff366c62ccf
+#             |          __libc_start_main
+#             |          _start             &lt;- callstack bottom
+#             |
+#              --24.55%--do_foo
+#                        main
+#                        0x7ff366c62ccf
+#                        __libc_start_main
+#                        _start             &lt;- callstack bottom
 </code></pre>
-<h3 id="insert-lines"><a class="header" href="#insert-lines">Insert lines</a></h3>
-<pre><code class="language-sh"># Insert before line.
-echo -e 'aa\nbb' | sed '2iABC'
-# aa
-# ABC
-# bb
-
-# Insert after line.
-echo -e 'aa\nbb' | sed '2aABC'
-# aa
-# bb
-# ABC
+<h2 id="references-3"><a class="header" href="#references-3">References</a></h2>
+<ul>
+<li><a href="https://github.com/intel/perfmon">intel/perfmon</a> - intel PMU event database per uarch</li>
+<li><a href="https://perfmon-events.intel.com/">intel/perfmon-html</a> - a html rendered version of the PMU
+events with search</li>
+<li><a href="https://github.com/intel/perfmon/blob/main/mapfile.csv">intel/perfmon/mapfile.csv</a> - processor family to uarch mapping</li>
+<li><a href="https://github.com/torvalds/linux/tree/master/tools/perf/pmu-events/arch/x86">linux/perf/events</a> - x86 PMU events known to perf tools</li>
+<li><a href="https://github.com/torvalds/linux/blob/master/arch/x86/events/intel/core.c">linux/arch/events</a> - x86 PMU events linux kernel</li>
+<li><a href="https://en.wikichip.org/wiki/WikiChip">wikichip</a> - computer architecture wiki</li>
+<li><a href="https://man7.org/linux/man-pages/man1/perf-list.1.html">perf-list(1)</a> - manpage</li>
+<li><a href="https://man7.org/linux/man-pages/man2/perf_event_open.2.html">perf_event_open(2)</a> - manpage</li>
+<li><a href="https://www.intel.com/content/www/us/en/developer/articles/technical/intel-sdm.html">intel/sdm</a> - intel software developer manuals (eg Optimization
+Reference Manual)</li>
+</ul>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="oprofile"><a class="header" href="#oprofile"><a href="https://oprofile.sourceforge.io/">OProfile</a></a></h1>
+<pre><code class="language-markdown">operf -g -p &lt;pid&gt;
+  -g ...... caputre call-graph information
 
-# Replace line.
-echo -e 'aa\nbb' | sed '2cABC'
-# aa
-# ABC
+opreport [opt] FILE
+            show time spent per binary image
+  -l ...... show time spent per symbol
+  -c ...... show callgraph information (see below)
+  -a ...... add column with time spent accumulated over child nodes
 
-# Insert before pattern match.
-echo -e 'aa\nbb' | sed '/bb/i 123'
-# aa
-# 123
-# bb
-</code></pre>
-<h3 id="substitute-lines"><a class="header" href="#substitute-lines">Substitute lines</a></h3>
-<pre><code class="language-sh"># Substitute by regex.
-echo -e 'aafooaa\ncc' | sed 's/foo/MOOSE/'
-# aaMOOSEaa
-# cc
+ophelp      show supported hw/sw events
 </code></pre>
-<h3 id="multiple-scripts"><a class="header" href="#multiple-scripts">Multiple scripts</a></h3>
-<pre><code class="language-sh">echo -e 'foo\nbar' | sed -e 's/foo/FOO/' -e 's/FOO/BAR/'
-# BAR
-# bar
+<div style="break-before: page; page-break-before: always;"></div><h1 id="callgrind"><a class="header" href="#callgrind">callgrind</a></h1>
+<p>Callgrind is a tracing profiler to record the function call history of a target
+program. It is part of the <a href="https://valgrind.org/docs/manual/cl-manual.html">valgrind</a> tool suite.</p>
+<p>Profiling data is collected by instrumentation rather than sampling of the
+target program.</p>
+<p>Callgrind does not capture the actual time spent in a function but computes the
+cost of a function based on the instructions fetched (<code>Ir = Instruction read</code>).
+Therefore effects like slow IO are not reflected, which should be kept in mind
+when analyzing callgrind results.</p>
+<p>By default the profiler data is dumped when the target process is terminating,
+but <a href="https://valgrind.org/docs/manual/cl-manual.html#cl-manual.callgrind_control-options">callgrind_control</a> allows for interactive control of callgrind.</p>
+<pre><code class="language-bash"># Run a program under callgrind.
+valgrind --tool=callgrind -- &lt;prog&gt;
+
+# Interactive control of callgrind.
+callgrind_control [opts]
+  opts:
+    -b ............. show current backtrace
+    -e ............. show current event counters
+    -s ............. show current stats
+    --dump[=file] .. dump current collection
+    -i=on|off ...... turn instrumentation on|off
 </code></pre>
-<h3 id="edit-inplace-through-symlink"><a class="header" href="#edit-inplace-through-symlink">Edit inplace through symlink</a></h3>
-<pre><code class="language-sh">touch file
-ln -s file link
-ls -l link
-# lrwxrwxrwx 1 johannst johannst 4 Feb  7 23:02 link -&gt; file
+<p>Results can be analyzed by using one of the following tools</p>
+<ul>
+<li><a href="https://valgrind.org/docs/manual/cl-manual.html#cl-manual.callgrind_annotate-options">callgrind_annotate</a> (cli)</li>
+<li><a href="https://kcachegrind.github.io/html/Home.html">kcachegrind</a> (ui)</li>
+</ul>
+<p>The following is a collection of frequently used callgrind options.</p>
+<pre><code class="language-bash">valgrind --tool=callgrind [opts] -- &lt;prog&gt;
+  opts:
+    --callgrind-out-file=&lt;file&gt; .... output file, rather than callgrind.out.&lt;pid&gt;
+    --dump-instr=&lt;yes|no&gt; .......... annotation on instrucion level,
+                                     allows for asm annotations
 
-sed -i --follow-symlinks '1iabc' link
-ls -l link
-# lrwxrwxrwx 1 johannst johannst 4 Feb  7 23:02 link -&gt; file
+    --instr-atstart=&lt;yes|no&gt; ....... control if instrumentation is enabled from 
+                                     beginning of the program
 
-sed -i '1iabc' link
-ls -l link
-# -rw-r--r-- 1 johannst johannst 0 Feb  7 23:02 link
+    --separate-threads=&lt;yes|no&gt; .... create separate output files per thread,
+                                     appends -&lt;thread_id&gt; to the output file
 </code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="gnuplot-1"><a class="header" href="#gnuplot-1">gnuplot (1)</a></h1>
-<pre><code># Launch interactive shell.
-gnuplot
+<h2 id="profile-specific-part-of-the-target"><a class="header" href="#profile-specific-part-of-the-target">Profile specific part of the target</a></h2>
+<p>Programmatically enable/disable instrumentation using the macros defined in
+the callgrind header.</p>
+<pre><code class="language-c">#include &lt;valgrind/callgrind.h&gt;
 
-# Launch interactive shell.
-gnuplot [opt]
-  opt:
-    -p ................ persist plot window
-    -c &lt;file&gt; ......... run script file
-    -e "&lt;cmd1&gt;; .." ... run cmd(s)
-</code></pre>
-<h2 id="frequently-used-configuration"><a class="header" href="#frequently-used-configuration">Frequently used configuration</a></h2>
-<pre><code class="language-sh"># Plot title.
-set title "the plot"
+int main() {
+    // init ..
 
-# Labels.
-set xlabel "abc"
-set ylabel "def"
+    CALLGRIND_START_INSTRUMENTATION;
+    compute();
+    CALLGRIND_STOP_INSTRUMENTATION;
 
-# Output format, 'help set term' for all output formats.
-set term svg
-# Output file.
-set output "out.svg"
+    // shutdown ..
+}
+</code></pre>
+<blockquote>
+<p>In this case, callgrind should be launched with <code>--instr-atstart=no</code>.</p>
+</blockquote>
+<p>Alternatively instrumentation can be controlled with <code>callgrind_control -i on/off</code>.</p>
+<p>The files <a href="trace_profile/callgrind/cg_example.cc">cg_example.cc</a> and
+<a href="trace_profile/callgrind/Makefile">Makefile</a> provide a full example.</p>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="debug-1"><a class="header" href="#debug-1">Debug</a></h1>
+<ul>
+<li><a href="debug/./gdb.html">gdb</a></li>
+<li><a href="debug/./gdbserver.html">gdbserver</a></li>
+</ul>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="gdb1"><a class="header" href="#gdb1">gdb(1)</a></h1>
+<h1 id="cli"><a class="header" href="#cli">CLI</a></h1>
+<pre><code class="language-markdown">  gdb [opts] [prg [-c coredump | -p pid]]
+  gdb [opts] --args prg &lt;prg-args&gt;
+    opts:
+      -p &lt;pid&gt;        attach to pid
+      -c &lt;coredump&gt;   use &lt;coredump&gt;
+      -x &lt;file&gt;       execute script &lt;file&gt; before prompt
+      -ex &lt;cmd&gt;       execute command &lt;cmd&gt; before prompt
+      --tty &lt;tty&gt;     set I/O tty for debugee
+      --batch         run in batch mode, exit after processing options (eg used
+                      for scripting)
+      --batch-silent  link --batch, but surpress gdb stdout
+</code></pre>
+<h1 id="interactive-usage"><a class="header" href="#interactive-usage">Interactive usage</a></h1>
+<h2 id="misc"><a class="header" href="#misc">Misc</a></h2>
+<pre><code class="language-markdown">  apropos &lt;regex&gt;
+          Search commands matching regex.
 
-# Make axis logarithmic to given base.
-set logscale x 2
+  tty &lt;tty&gt;
+          Set &lt;tty&gt; as tty for debugee.
+          Make sure nobody reads from target tty, easiest is to spawn a shell
+          and run following in target tty:
+          &gt; while true; do sleep 1024; done
 
-# Change separator, default is whitespace.
-set datafile separator ","
-</code></pre>
-<h2 id="plot"><a class="header" href="#plot">Plot</a></h2>
-<pre><code class="language-sh"># With specific style (eg lines, linespoint, boxes, steps, impulses, ..).
-plot "&lt;data_file&gt;" with &lt;plot_style&gt;
+  sharedlibrary [&lt;regex&gt;]
+          Load symbols of shared libs loaded by debugee. Optionally use &lt;regex&gt;
+          to filter libs for symbol loading.
 
-&gt; cat data.txt
-1 1 3
-2 2 2
-3 3 1
-4 2 2
+  display [/FMT] &lt;expr&gt;
+          Print &lt;expr&gt; every time debugee stops. Eg print next instr, see
+          examples below.
 
-# Plot specific column.
-plot "data.txt" using 1:2, "data.txt" using 1:3
-# Equivalent using the special file "", which re-uses the previous input file.
-plot "data.txt" using 1:2, "" using 1:3
+  undisplay [&lt;num&gt;]
+          Delete display expressions either all or one referenced by &lt;num&gt;.
 
-# Plot piped data.
-plot "&lt; head -n2 data.txt"
+  info display
+          List display expressions.
 
-# Plot with alternate title.
-plot "data.txt" title "moose"
+  info sharedlibrary [&lt;regex&gt;]
+          List shared libraries loaded. Optionally use &lt;regex&gt; to filter.
 </code></pre>
-<h2 id="example-multiple-data-sets-in-on-plot"><a class="header" href="#example-multiple-data-sets-in-on-plot">Example: multiple data sets in on plot</a></h2>
-<pre><code class="language-sh"># file: mem_lat.plot
+<h2 id="breakpoints"><a class="header" href="#breakpoints">Breakpoints</a></h2>
+<pre><code class="language-markdown">  break [-qualified] &lt;sym&gt; thread &lt;tnum&gt;
+          Set a breakpoint only for a specific thread.
+          -qualified: Treat &lt;sym&gt; as fully qualified symbol (quiet handy to set
+          breakpoints on C symbols in C++ contexts)
 
-set title  "memory latency (different strides)"
-set xlabel "array in KB"
-set ylabel "cycles / access"
+  break &lt;sym&gt; if &lt;cond&gt;
+          Set conditional breakpoint (see examples below).
 
-set logscale x 2
+  delete [&lt;num&gt;]
+          Delete breakpoint either all or one referenced by &lt;num&gt;.
 
-plot "stride_32.txt"  title "32"  with linespoints, \
-     "stride_64.txt"  title "64"  with linespoints, \
-     "stride_128.txt" title "128" with linespoints, \
-     "stride_256.txt" title "256" with linespoints, \
-     "stride_512.txt" title "512" with linespoints
-</code></pre>
-<p>On Linux x86_64, <a href="tools/gnuplot/mem_lat.c"><code>mem_lat.c</code></a> provides an example which can
-be run as follows.</p>
-<pre><code class="language-sh">gcc -o mem_lat mem_lat.c -g -O3 -Wall -Werror
+  info break
+          List breakpoints.
 
-for stride in 32 64 128 256 512; do \
-    taskset -c 1 ./mem_lat 128 $stride | tee stride_$stride.txt ; \
-done
+  cond &lt;bp&gt; &lt;cond&gt;
+          Make existing breakpoint &lt;bp&gt; conditional with &lt;cond&gt;.
 
-gnuplot -p -c mem_lat.plot
-</code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="resource-analysis--monitor"><a class="header" href="#resource-analysis--monitor">Resource analysis &amp; monitor</a></h1>
-<ul>
-<li><a href="monitor/./lsof.html">lsof</a></li>
-<li><a href="monitor/./ss.html">ss</a></li>
-<li><a href="monitor/./pidstat.html">pidstat</a></li>
-<li><a href="monitor/./pgrep.html">pgrep</a></li>
-<li><a href="monitor/./ps.html">ps</a></li>
-<li><a href="monitor/./pmap.html">pmap</a></li>
-<li><a href="monitor/./pstack.html">pstack</a></li>
-</ul>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="lsof8"><a class="header" href="#lsof8">lsof(8)</a></h1>
-<pre><code class="language-markdown">lsof
-  -r &lt;s&gt; ..... repeatedly execute command ervery &lt;s&gt; seconds
-  -a ......... AND slection filters instead ORing (OR: default)
-  -p &lt;pid&gt; ... filter by &lt;pid&gt;
-  +fg ........ show file flags for file descripros
-  -n ......... don't convert network addr to hostnames
-  -P ......... don't convert network port to service names
-  -i &lt;@h[:p]&gt;. show connections to h (hostname|ip addr) with optional port p
-  -s &lt;p:s&gt; ... in conjunction with '-i' filter for protocol &lt;p&gt; in state &lt;s&gt;
-  -U ......... show unix domain sockets ('@' indicates abstract sock name, see unix(7))
-</code></pre>
-<pre><code class="language-markdown">file flags:
-  R/W/RW ..... read/write/read-write
-  CR ......... create
-  AP ......... append
-  TR ......... truncate
-</code></pre>
-<pre><code class="language-markdown">-s protocols
-  TCP, UDP
+  cond &lt;bp&gt;
+          Remove condition from breakpoint &lt;bp&gt;.
 
--s states (TCP)
-  CLOSED, IDLE, BOUND, LISTEN, ESTABLISHED, SYN_SENT, SYN_RCDV, ESTABLISHED,
-  CLOSE_WAIT, FIN_WAIT1, CLOSING, LAST_ACK, FIN_WAIT_2, TIME_WAIT
+  tbreak
+          Set temporary breakpoint, will be deleted when hit.
+          Same syntax as `break`.
 
--s states (UDP)
-  Unbound, Idle
-</code></pre>
-<h1 id="examples-7"><a class="header" href="#examples-7">Examples</a></h1>
-<h2 id="file-flags"><a class="header" href="#file-flags">File flags</a></h2>
-<p>Show open files with file flags for process:</p>
-<pre><code class="language-markdown">lsof +fg -p &lt;pid&gt;
-</code></pre>
-<h2 id="open-tcp-connections"><a class="header" href="#open-tcp-connections">Open TCP connections</a></h2>
-<p>Show open tcp connections for <code>$USER</code>:</p>
-<pre><code class="language-markdown">lsof -a -u $USER -i TCP
-</code></pre>
-<p><strong>Note</strong>: <code>-a</code> <em>ands</em> the results. If <code>-a</code> is not given all open files matching
-<code>$USER</code> and all tcp connections are listed (<em>ored</em>).</p>
-<h2 id="open-connection-to-specific-host"><a class="header" href="#open-connection-to-specific-host">Open connection to specific host</a></h2>
-<p>Show open connections to <code>localhost</code> for <code>$USER</code>:</p>
-<pre><code class="language-markdown">lsof -a -u $USER -i @localhost
-</code></pre>
-<h2 id="open-connection-to-specific-port"><a class="header" href="#open-connection-to-specific-port">Open connection to specific port</a></h2>
-<p>Show open connections to port <code>:1234</code> for <code>$USER</code>:</p>
-<pre><code class="language-markdown">lsof -a -u $USER -i :1234
-</code></pre>
-<h2 id="ipv4-tcp-connections-in-established-state"><a class="header" href="#ipv4-tcp-connections-in-established-state">IPv4 TCP connections in <code>ESTABLISHED</code> state</a></h2>
-<pre><code class="language-markdown">lsof -i 4TCP -s TCP:ESTABLISHED
-</code></pre>
-<h2 id="list-open-files-in-a-mounted-directory"><a class="header" href="#list-open-files-in-a-mounted-directory">List open files in a mounted directory.</a></h2>
-<p>This may help to find which processes keep devices busy when trying to unmount
-and the device is currently busy.</p>
-<pre><code class="language-markdown"># Assuming /proc is a mount point.
-lsof /proc
-</code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="ss8"><a class="header" href="#ss8">ss(8)</a></h1>
-<pre><code class="language-markdown">ss [option] [filter]
-</code></pre>
-<pre><code class="language-markdown">[option]
-  -p ..... Show process using socket
-  -l ..... Show sockets in listening state
-  -4/-6 .. Show IPv4/6 sockets
-  -x ..... Show unix sockets
-  -n ..... Show numeric ports (no resolve)
-  -O ..... Oneline output per socket
-</code></pre>
-<pre><code class="language-markdown">[filter]
-  dport/sport PORT .... Filter for destination/source port
-  dst/src ADDR ........ Filter for destination/source address
+  rbreak &lt;regex&gt;
+          Set breakpoints matching &lt;regex&gt;, where matching internally is done
+          on: .*&lt;regex&gt;.*
 
-  and/or .............. Logic operator
-  ==/!= ............... Comparison operator
+  command [&lt;bp_list&gt;]
+          Define commands to run after breakpoint hit. If &lt;bp_list&gt; is not
+          specified attach command to last created breakpoint. Command block
+          terminated with 'end' token.
 
-  (EXPR) .............. Group exprs
-</code></pre>
-<h1 id="examples-8"><a class="header" href="#examples-8">Examples</a></h1>
-<p>Show all tcp IPv4 sockets connecting to port <code>443</code>:</p>
-<pre><code class="language-markdown">ss -4 'dport 443'
-</code></pre>
-<p>Show all tcp IPv4 sockets that don't connect to port <code>443</code> or connect to address <code>1.2.3.4</code>.</p>
-<pre><code class="language-markdown">ss -4 'dport != 443 or dst 1.2.3.4'
-</code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="pidstat1"><a class="header" href="#pidstat1">pidstat(1)</a></h1>
-<pre><code class="language-markdown">pidstat [opt] [interval] [cont]
-  -U [user]     show username instead UID, optionally only show for user
-  -r            memory statistics
-  -d            I/O statistics
-  -h            single line per process and no lines with average
-</code></pre>
-<h1 id="page-fault-and-memory-utilization"><a class="header" href="#page-fault-and-memory-utilization">Page fault and memory utilization</a></h1>
-<pre><code class="language-markdown">pidstat -r -p &lt;pid&gt; [interval] [count]
-</code></pre>
-<pre><code class="language-markdown">minor_pagefault: Happens when the page needed is already in memory but not
-                 allocated to the faulting process, in that case the kernel
-                 only has to create a new page-table entry pointing to the
-                 shared physical page (not required to load a memory page from
-                 disk).
+          &lt;bp_list&gt;: Space separates list, eg 'command 2 5-8' to run command
+          for breakpoints: 2,5,6,7,8.
 
-major_pagefault: Happens when the page needed is NOT in memory, the kernel
-                 has to create a new page-table entry and populate the
-                 physical page (required to load a memory page from disk).
-</code></pre>
-<h1 id="io-statistics"><a class="header" href="#io-statistics">I/O statistics</a></h1>
-<pre><code class="language-markdown">pidstat -d -p &lt;pid&gt; [interval] [count]
-</code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="pgrep1"><a class="header" href="#pgrep1">pgrep(1)</a></h1>
-<pre><code class="language-markdown">pgrep [opts] &lt;pattern&gt;
-  -n         only list newest matching process
-  -u &lt;usr&gt;   only show matching for user &lt;usr&gt;
-  -l         additionally list command
-  -a         additionally list command + arguments
-  -x         match exactly
-</code></pre>
-<h2 id="debug-newest-process"><a class="header" href="#debug-newest-process">Debug newest process</a></h2>
-<p>For example attach gdb to newest zsh process from <code>$USER</code>.</p>
-<pre><code class="language-markdown">gdb -p $(pgrep -n -u $USER zsh)
-</code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="ps1"><a class="header" href="#ps1">ps(1)</a></h1>
-<pre><code>ps [opt]
-  opt:
-    --no-header .... do not print column header
-    -o &lt;OUT&gt; ....... comma separated list of output columns
-    -p &lt;PID&gt; ....... only show pid
-    -C &lt;name&gt; ...... only show processes matching name
-    -T ............. list threads
-    --signames ..... use short signames instead bitmasks
+  save break &lt;file&gt;
+          Save breakpoints to &lt;file&gt;. Can be loaded with the `source` command.
 </code></pre>
-<blockquote>
-<p>Set <code>PS_FORMAT</code> env variable to setup default output columns.</p>
-</blockquote>
-<p>Frequently used output columns</p>
-<pre><code>pid        process id
-ppid       parent process id
-pgid       process group id
-tid        thread id
+<h2 id="watchpoints"><a class="header" href="#watchpoints">Watchpoints</a></h2>
+<pre><code class="language-markdown">  watch [-location|-l] &lt;expr&gt; [thread &lt;tnum&gt;]
+          Create a watchpoint for &lt;expr&gt;, will break if &lt;expr&gt; is written to.
+          Watchpoints respect scope of variables, -l can be used to watch the
+          memory location instead.
 
-comm       name of process
-cmd        name of process + args (full)
+  rwatch ...
+          Sets a read watchpoint, will break if &lt;expr&gt; is read from.
 
-etime      elapsed time (since process started)
-user       user owning process
-thcount    thread count of process
-nice       nice value (-20 highest priority to 19 lowest)
+  awatch ...
+          Sets an access watchpoint, will break if &lt;expr&gt; is written to or read
+          from.
+</code></pre>
+<h2 id="catchpoints"><a class="header" href="#catchpoints">Catchpoints</a></h2>
+<pre><code class="language-markdown">  catch load [&lt;regex&gt;]
+          Stop when shared libraries are loaded, optionally specify a &lt;regex&gt;
+          to stop only on matches.
+  catch unload [&lt;regex&gt;]
+          Stop when shared libraries are unloaded, optionally specify a &lt;regex&gt;
+          to stop only on matches.
 
-pcpu       cpu utilization (percent)
-pmem       physical resident set (rss) (percent)
-rss        physical memory (in kb)
-vsz        virtual memory (in kb)
+  catch throw
+          Stop when an exception is thrown.
+  catch rethrow
+          Stop when an exception is rethrown.
+  catch catch
+          Stop when an exception is caught.
 
-sig        mask of pending signals
-sigcatch   mask of caught signals
-sigignore  mask of ignored signals
-sigmask    mask of blocked signals
-</code></pre>
-<h2 id="example-use-output-for-scripting"><a class="header" href="#example-use-output-for-scripting">Example: Use output for scripting</a></h2>
-<pre><code class="language-sh">for tid in $(ps -o tid --no-header -T -p 31084); do
-    taskset -c -p $tid;
-done
-</code></pre>
-<h2 id="example-watch-processes-by-name"><a class="header" href="#example-watch-processes-by-name">Example: Watch processes by name</a></h2>
-<pre><code class="language-sh">watch -n1 ps -o pid,pcpu,pmem,rss,vsz,state,user,comm -C fish
-</code></pre>
-<h2 id="example-show-signal-information"><a class="header" href="#example-show-signal-information">Example: Show signal information</a></h2>
-<pre><code class="language-sh"># With signal masks.
-ps -o pid,user,sig,sigcatch,sigignore,sigmask,comm -p 66570
+  catch fork
+          Stop at calls to fork (also stops at clones, as some systems
+          implement fork via clone).
 
-# With signal names.
-ps --signames -o pid,user,sig,sigcatch,sigignore,sigmask,comm -p 66570
-</code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="pmap1"><a class="header" href="#pmap1">pmap(1)</a></h1>
-<pre><code class="language-markdown">pmap [opts] &lt;pid&gt;
-    Dump virtual memory map of process.
-    Compared to /proc/&lt;pid&gt;/maps it shows the size of the mappings.
-opts:
-  -p         show full path in the mapping
-  -x         show details (eg RSS usage of each segment)
-</code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="pstack1"><a class="header" href="#pstack1">pstack(1)</a></h1>
-<pre><code class="language-markdown">pstack &lt;pid&gt;
-    Dump stack for all threads of process.
+  catch syscall [&lt;syscall&gt; &lt;syscall&gt; ..]
+          Stop at syscall. If no argument is given, stop at all syscalls.
+          Optionally give a list of syscalls to stop at.
 </code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="trace-and-profile"><a class="header" href="#trace-and-profile">Trace and Profile</a></h1>
-<ul>
-<li><a href="trace_profile/./time.html">time</a></li>
-<li><a href="trace_profile/./strace.html">strace</a></li>
-<li><a href="trace_profile/./ltrace.html">ltrace</a></li>
-<li><a href="trace_profile/./perf.html">perf</a></li>
-<li><a href="trace_profile/./oprofile.html">OProfile</a></li>
-<li><a href="trace_profile/./callgrind.html">callgrind</a></li>
-</ul>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="usrbintime1"><a class="header" href="#usrbintime1">/usr/bin/time(1)</a></h1>
-<pre><code class="language-markdown"># statistics of process run
-/usr/bin/time -v &lt;cmd&gt;
+<h2 id="inspection"><a class="header" href="#inspection">Inspection</a></h2>
+<pre><code class="language-markdown">  info functions [&lt;regex&gt;]
+          List functions matching &lt;regex&gt;. List all functions if no &lt;regex&gt;
+          provided.
+
+  info variables [&lt;regex&gt;]
+          List variables matching &lt;regex&gt;. List all variables if no &lt;regex&gt;
+          provided.
+
+  info register [&lt;reg&gt; &lt;reg&gt; ..]
+          Dump content of all registers or only the specified &lt;reg&gt;ister.
 </code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="strace1"><a class="header" href="#strace1">strace(1)</a></h1>
-<pre><code class="language-markdown">strace [opts] [prg]
-  -f .......... follow child processes on fork(2)
-  -ff ......... follow fork and separate output file per child
-  -p &lt;pid&gt; .... attach to running process
-  -s &lt;size&gt; ... max string size, truncate of longer (default: 32)
-  -e &lt;expr&gt; ... expression for trace filtering
-  -o &lt;file&gt; ... log output into &lt;file&gt;
-  -c .......... dump syscall statitics at the end
-  -C .......... like -c but dump regular ouput as well
-  -k .......... dump stack trace for each syscall
-  -P &lt;path&gt; ... only trace syscall accesing path
-  -y .......... print paths for FDs
-  -tt ......... print absolute timestamp (with us precision)
-  -r .......... print relative timestamp
-  -z .......... log only successful syscalls
-  -Z .......... log only failed syscalls
-  -n .......... print syscall numbers
-  -y .......... translate fds (eg file path, socket)
-  -yy ......... translate fds with all information (eg IP)
-  -x .......... print non-ASCII chars as hex string
+<h2 id="signal-handling"><a class="header" href="#signal-handling">Signal handling</a></h2>
+<pre><code class="language-markdown">  info handle [&lt;signal&gt;]
+          Print how to handle &lt;signal&gt;. If no &lt;signal&gt; specified print for all
+          signals.
+
+  handle &lt;signal&gt; &lt;action&gt;
+          Configure how gdb handles &lt;signal&gt; sent to debugee.
+          &lt;action&gt;:
+            stop/nostop       Catch signal in gdb and break.
+            print/noprint     Print message when gdb catches signal.
+            pass/nopass       Pass signal down to debugee.
+
+  catch signal &lt;signal&gt;
+          Create a catchpoint for &lt;signal&gt;.
 </code></pre>
-<pre><code class="language-markdown">&lt;expr&gt;:
-  trace=syscall[,syscall] .... trace only syscall listed
-  trace=file ................. trace all syscall that take a filename as arg
-  trace=process .............. trace process management related syscalls
-  trace=signal ............... trace signal related syscalls
-  signal ..................... trace signals delivered to the process
+<h2 id="multi-threading"><a class="header" href="#multi-threading">Multi-threading</a></h2>
+<pre><code class="language-markdown">info thread
+          List all threads.
+
+thread apply &lt;id&gt; [&lt;id&gt;] &lt;command&gt;
+          Run command on all threads listed by &lt;id&gt; (space separated list).
+          When 'all' is specified as &lt;id&gt; the &lt;command&gt; is run on all threads.
+
+thread name &lt;name&gt;
+          The &lt;name&gt; for the current thread.
 </code></pre>
-<h1 id="examples-9"><a class="header" href="#examples-9">Examples</a></h1>
-<p>Trace <code>open(2)</code> &amp; <code>socket(2)</code> syscalls for a running process + child processes:</p>
-<pre><code class="language-markdown">strace -f -e trace=open,socket -p &lt;pid&gt;
+<h2 id="multi-process"><a class="header" href="#multi-process">Multi-process</a></h2>
+<pre><code class="language-markdown">  set follow-fork-mode &lt;child | parent&gt;
+          Specify which process to follow when debuggee makes a fork(2)
+          syscall.
+
+  set detach-on-fork &lt;on | off&gt;
+          Turn on/off detaching from new child processes (on by default).
+          Turning this off allows to debug multiple processes (inferiors) with
+          one gdb session.
+
+  info inferiors
+          List all processes gdb debugs.
+
+  inferior &lt;id&gt;
+          Switch to inferior with &lt;id&gt;.
 </code></pre>
-<p>Trace signals delivered to a running process:</p>
-<pre><code class="language-markdown">strace -e signal -e 'trace=!all' -p &lt;pid&gt;
+<h2 id="scheduling"><a class="header" href="#scheduling">Scheduling</a></h2>
+<pre><code class="language-markdown">  set schedule-multiple &lt;on | off&gt;
+          on: Resume all threads of all processes (inferiors) when continuing
+              or stepping.
+          off: (default) Resume only threads of current process (inferior).
 </code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="ltrace1"><a class="header" href="#ltrace1">ltrace(1)</a></h1>
-<pre><code class="language-markdown">ltrace [opts] [prg]
-  -f .......... follow child processes on fork(2)
-  -p &lt;pid&gt; .... attach to running process
-  -o &lt;file&gt; ... log output into &lt;file&gt;
-  -l &lt;filter&gt; . show who calls into lib matched by &lt;filter&gt;
-  -C .......... demangle
+<h2 id="shell-commands"><a class="header" href="#shell-commands">Shell commands</a></h2>
+<pre><code class="language-markdown">  shell &lt;shell_cmd&gt;
+          Run the shell_cmd and print the output, can also contain a pipeline.
+
+  pipe &lt;gdb_cmd&gt; | &lt;shell_cmd&gt;
+          Evaluate the gdb_cmd and run the shell_cmd which receives the output
+          of the gdb_cmd via stdin.
 </code></pre>
-<h1 id="example-5"><a class="header" href="#example-5">Example</a></h1>
-<p>List which program/libs call into <code>libstdc++</code>:</p>
-<pre><code class="language-bash">ltrace -l '*libstdc++*' -C -o ltrace.log ./main
+<h2 id="source-file-locations"><a class="header" href="#source-file-locations">Source file locations</a></h2>
+<pre><code class="language-markdown">  dir &lt;path&gt;
+          Add &lt;path&gt; to the beginning of the searh path for source files.
+
+  show dir
+          Show current search path.
+
+  set substitute-path &lt;from&gt; &lt;to&gt;
+          Add substitution rule checked during source file lookup.
+
+  show substitute-path
+          Show current substitution rules.
 </code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="perf1"><a class="header" href="#perf1">perf(1)</a></h1>
-<pre><code>perf list     show supported hw/sw events &amp; metrics
-  -v ........ print longer event descriptions
-  --details . print information on the perf event names
-              and expressions used internally by events
+<h2 id="configuration"><a class="header" href="#configuration">Configuration</a></h2>
+<pre><code class="language-markdown">  set disassembly-flavor &lt;intel | att&gt;
+          Set the disassembly style "flavor".
 
-perf stat
-  -p &lt;pid&gt; ..... show stats for running process
-  -o &lt;file&gt; .... write output to file (default stderr)
-  -I &lt;ms&gt; ...... show stats periodically over interval &lt;ms&gt;
-  -e &lt;ev&gt; ...... select event(s)
-  -M &lt;met&gt; ..... print metric(s), this adds the metric events
-  --all-user ... configure all selected events for user space
-  --all-kernel . configure all selected events for kernel space
+  set pagination &lt;on | off&gt;
+          Turn on/off gdb's pagination.
 
-perf top
-  -p &lt;pid&gt; .. show stats for running process
-  -F &lt;hz&gt; ... sampling frequency
-  -K ........ hide kernel threads
+  set breakpoint pending &lt;on | off | auto&gt;
+          on: always set pending breakpoints.
+          off: error when trying to set pending breakpoints.
+          auto: interatively query user to set breakpoint.
 
-perf record
-  -p &lt;pid&gt; ............... record stats for running process
-  -o &lt;file&gt; .............. write output to file (default perf.data)
-  -F &lt;hz&gt; ................ sampling frequency
-  --call-graph &lt;method&gt; .. [fp, dwarf, lbr] method how to caputre backtrace
-                           fp   : use frame-pointer, need to compile with
-                                  -fno-omit-frame-pointer
-                           dwarf: use .cfi debug information
-                           lbr  : use hardware last branch record facility
-  -g ..................... short-hand for --call-graph fp
-  -e &lt;ev&gt; ................ select event(s)
-  --all-user ............. configure all selected events for user space
-  --all-kernel ........... configure all selected events for kernel space
-  -M intel ............... use intel disassembly in annotate
+  set print pretty &lt;on | off&gt;
+          Turn on/off pertty printing of structures.
 
-perf report
-  -n .................... annotate symbols with nr of samples
-  --stdio ............... report to stdio, if not presen tui mode
-  -g graph,0.5,callee ... show callee based call chains with value &gt;0.5
-</code></pre>
-<pre><code>Useful &lt;ev&gt;:
-  page-faults
-  minor-faults
-  major-faults
-  cpu-cycles`
-  task-clock
+  set style enabled &lt;on | off&gt;
+          Turn on/off styling (eg colored output).
+
+  set logging &lt;on | off&gt;
+          Enable output logging to file (default gdb.txt).
+
+  set logging file &lt;fname&gt;
+          Change output log file to &lt;fname&gt;
+
+  set logging redirect &lt;on | off&gt;
+          on: only log to file.
+          off: log to file and tty.
+
+  set logging overwrite &lt;on | off&gt;
+          on: Truncate log file on each run.
+          off: Append to logfile (default).
+
+  set history filename &lt;fname&gt;
+          Change file where to save and restore command history to and from.
+
+  set history &lt;on | off&gt;
+          Enable or disable saving of command history.
 </code></pre>
-<h2 id="select-specific-events"><a class="header" href="#select-specific-events">Select specific events</a></h2>
-<p>Events to sample are specified with the <code>-e</code> option, either pass a comma
-separated list or pass <code>-e</code> multiple times.</p>
-<p>Events are specified in the following form <code>name[:modifier]</code>. The list and
-description of the <code>modifier</code> can be found in the
-<a href="https://man7.org/linux/man-pages/man1/perf-list.1.html"><code>perf-list(1)</code></a> manpage under <code>EVENT MODIFIERS</code>.</p>
-<pre><code class="language-sh"># L1 i$ misses in user space
-# L2 i$ stats in user/kernel space mixed
-# Sample specified events.
-perf stat -e L1-icache-load-misses:u \
-          -e l2_rqsts.all_code_rd:uk,l2_rqsts.code_rd_hit:k,l2_rqsts.code_rd_miss:k \
-          -- stress -c 2
+<blockquote>
+<p>Logging options should be configured before logging is turned on.</p>
+</blockquote>
+<h1 id="text-user-interface-tui"><a class="header" href="#text-user-interface-tui">Text user interface (TUI)</a></h1>
+<pre><code class="language-markdown">  C-x a     Toggle UI.
+  C-l       Redraw UI (curses UI can be messed up after the debugee prints to
+            stdout/stderr).
+  C-x o     Change focus.
 </code></pre>
-<p>The <code>--all-user</code> and <code>--all-kernel</code> options append a <code>:u</code> and <code>:k</code> modifier to
-all specified events. Therefore the following two command lines are equivalent.</p>
-<pre><code class="language-sh"># 1)
-perf stat -e cycles:u,instructions:u -- ls
+<h1 id="user-commands-macros"><a class="header" href="#user-commands-macros">User commands (macros)</a></h1>
+<p>Gdb allows to create &amp; document user commands as follows:</p>
+<pre><code class="language-markdown">  define &lt;cmd&gt;
+    # cmds
+  end
 
-# 2)
-perf stat --all-user -e cycles,instructions -- ls
+  document &lt;cmd&gt;
+    # docu
+  end
 </code></pre>
-<h3 id="raw-events"><a class="header" href="#raw-events">Raw events</a></h3>
-<p>In case perf does not provide a <em>symbolic</em> name for an event, the event can be
-specified in a <em>raw</em> form as <code>r + UMask + EventCode</code>.</p>
-<p>The following is an example for the <a href="https://github.com/intel/perfmon/blob/09c155f72e1b8f14b09aea346a35467a03a7d62b/SNB/events/sandybridge_core.json#L808">L2_RQSTS.CODE_RD_HIT</a> event
-with <code>EventCode=0x24</code> and <code>UMask=0x10</code> on my laptop with a <code>sandybridge</code> uarch.</p>
-<pre><code class="language-sh">perf stat -e l2_rqsts.code_rd_hit -e r1024 -- ls
-# Performance counter stats for 'ls':
-#
-#       33.942      l2_rqsts.code_rd_hit
-#       33.942      r1024
+<p>To get all user commands or documentations one can use:</p>
+<pre><code class="language-markdown">  help user-defined
+  help &lt;cmd&gt;
 </code></pre>
-<h3 id="find-raw-performance-counter-events-intel"><a class="header" href="#find-raw-performance-counter-events-intel">Find raw performance counter events (intel)</a></h3>
-<p>The <a href="https://github.com/intel/perfmon"><code>intel/perfmon</code></a> repository provides a performance event
-databases for the different intel uarchs.</p>
-<p>The table in <a href="https://github.com/intel/perfmon/blob/main/mapfile.csv"><code>mapfile.csv</code></a> can be used to lookup the
-corresponding uarch, just grab the family model from the procfs.</p>
-<pre><code class="language-sh"> cat /proc/cpuinfo | awk '/^vendor_id/  { V=$3 }
-                          /^cpu family/ { F=$4 }
-                          /^model\s*:/  { printf "%s-%d-%x\n",V,F,$3 }'
+<h1 id="hooks"><a class="header" href="#hooks">Hooks</a></h1>
+<p>Gdb allows to create two types of command <code>hooks</code></p>
+<ul>
+<li><code>hook-</code> will be run before <code>&lt;cmd&gt;</code></li>
+<li><code>hookpost-</code> will be run after <code>&lt;cmd&gt;</code></li>
+</ul>
+<pre><code class="language-markdown">  define hook-&lt;cmd&gt;
+    # cmds
+  end
+
+  define hookpost-&lt;cmd&gt;
+    # cmds
+  end
 </code></pre>
-<blockquote>
-<p>The table in <a href="https://github.com/intel/perfmon/tree/main#performance-monitoring-events">performance monitoring events</a> describes how
-events are sorted into the different files.</p>
-</blockquote>
-<h3 id="raw-events-for-perfs-own-symbolic-names"><a class="header" href="#raw-events-for-perfs-own-symbolic-names">Raw events for perfs own symbolic names</a></h3>
-<p>Perf also defines some own <em>symbolic</em> names for events. An example is the
-<code>cache-references</code> event. The <a href="https://man7.org/linux/man-pages/man2/perf_event_open.2.html"><code>perf_event_open(2)</code></a> manpage
-gives the following description.</p>
-<pre><code class="language-man">perf_event_open(2)
+<h1 id="examples-10"><a class="header" href="#examples-10">Examples</a></h1>
+<h2 id="automatically-print-next-instr"><a class="header" href="#automatically-print-next-instr">Automatically print next instr</a></h2>
+<p>When ever the debugee stops automatically print the memory at the current
+instruction pointer (<code>$rip</code> x86) and format as instruction <code>/i</code>.</p>
+<pre><code class="language-markdown">  # rip - x86
+  display /i $rip
 
-PERF_COUNT_HW_CACHE_REFERENCES
-    Cache accesses.  Usually this indicates Last Level Cache accesses but this
-    may vary depending on your CPU.  This may include prefetches and coherency
-    messages; again this depends on the design of your CPU.
+  # step instruction, after the step the next instruction is automatically printed
+  si
 </code></pre>
-<p>The <code>sysfs</code> can be consulted to get the concrete performance counter on the
-given system.</p>
-<pre><code class="language-sh">cat /sys/devices/cpu/events/cache-misses
-# event=0x2e,umask=0x41
+<h2 id="conditional-breakpoints"><a class="header" href="#conditional-breakpoints">Conditional breakpoints</a></h2>
+<p>Create conditional breakpoints for a function <code>void foo(int i)</code> in the debugee.</p>
+<pre><code class="language-markdown">  # Create conditional breakpoint
+  b foo if i == 42
+
+  b foo     # would create bp 2
+  # Make existing breakpoint conditional
+  cond 2 i == 7
 </code></pre>
-<h2 id="flamegraph"><a class="header" href="#flamegraph"><a href="https://github.com/brendangregg/FlameGraph"><code>Flamegraph</code></a></a></h2>
-<h3 id="flamegraph-with-single-event-trace"><a class="header" href="#flamegraph-with-single-event-trace">Flamegraph with single event trace</a></h3>
-<pre><code>perf record -g -e cpu-cycles -p &lt;pid&gt;
-perf script | FlameGraph/stackcollapse-perf.pl | FlameGraph/flamegraph.pl &gt; cycles-flamegraph.svg
+<h2 id="set-breakpoint-on-all-threads-except-one"><a class="header" href="#set-breakpoint-on-all-threads-except-one">Set breakpoint on all threads except one</a></h2>
+<p>Create conditional breakpoint using the <code>$_thread</code> <a href="https://sourceware.org/gdb/onlinedocs/gdb/Convenience-Vars.html#Convenience-Vars">convenience
+variable</a>.</p>
+<pre><code class="language-markdown">  # Create conditional breakpoint on all threads except thread 12.
+  b foo if $_thread != 12
 </code></pre>
-<h3 id="flamegraph-with-multiple-event-traces"><a class="header" href="#flamegraph-with-multiple-event-traces">Flamegraph with multiple event traces</a></h3>
-<pre><code class="language-sh">perf record -g -e cpu-cycles,page-faults -p &lt;pid&gt;
-perf script --per-event-dump
-# fold &amp; generate as above
+<h2 id="catch-sigsegv-and-execute-commands"><a class="header" href="#catch-sigsegv-and-execute-commands">Catch SIGSEGV and execute commands</a></h2>
+<p>This creates a <code>catchpoint</code> for the <code>SIGSEGV</code> signal and attached the <code>command</code>
+to it.</p>
+<pre><code class="language-markdown">  catch signal SIGSEGV
+  command
+    bt
+    c
+  end
 </code></pre>
-<h2 id="examples-10"><a class="header" href="#examples-10">Examples</a></h2>
-<h3 id="estimate-max-instructions-per-cycle"><a class="header" href="#estimate-max-instructions-per-cycle">Estimate max instructions per cycle</a></h3>
-<pre><code class="language-c">#define NOP4        "nop\nnop\nnop\nnop\n"
-#define NOP32       NOP4   NOP4   NOP4   NOP4   NOP4   NOP4   NOP4   NOP4
-#define NOP256      NOP32  NOP32  NOP32  NOP32  NOP32  NOP32  NOP32  NOP32
-#define NOP2048     NOP256 NOP256 NOP256 NOP256 NOP256 NOP256 NOP256 NOP256
+<h2 id="run-backtrace-on-thread-1-batch-mode"><a class="header" href="#run-backtrace-on-thread-1-batch-mode">Run <code>backtrace</code> on thread 1 (batch mode)</a></h2>
+<pre><code class="language-markdown">  gdb --batch -ex 'thread 1' -ex 'bt' -p &lt;pid&gt;
+</code></pre>
+<h2 id="script-gdb-for-automating-debugging-sessions"><a class="header" href="#script-gdb-for-automating-debugging-sessions">Script gdb for automating debugging sessions</a></h2>
+<p>To script gdb add commands into a file and pass it to gdb via <code>-x</code>.
+For example create <code>run.gdb</code>:</p>
+<pre><code class="language-markdown">  set pagination off
+
+  break mmap
+  command
+    info reg rdi rsi rdx
+    bt
+    c
+  end
 
-int main() {
-  for (unsigned i = 0; i &lt; 2000000; ++i) {
-    asm volatile(NOP2048);
-  }
-}
+  #initial drop
+  c
 </code></pre>
-<pre><code class="language-sh">perf stat -e cycles,instructions ./noploop
-# Performance counter stats for './noploop':
-#
-#     1.031.075.940      cycles
-#     4.103.534.341      instructions       #    3,98  insn per cycle
+<p>This script can be used as:</p>
+<pre><code class="language-markdown">  gdb --batch -x ./run.gdb -p &lt;pid&gt;
 </code></pre>
-<h3 id="caller-vs-callee-callstacks"><a class="header" href="#caller-vs-callee-callstacks">Caller vs callee callstacks</a></h3>
-<p>The following gives an example for a scenario where we have the following calls</p>
-<ul>
-<li><code>main -&gt; do_foo() -&gt; do_work()</code></li>
-<li><code>main -&gt; do_bar() -&gt; do_work()</code></li>
-</ul>
-<pre><code class="language-sh">perf report --stdio -g graph,callee
+<h2 id="hook-to-automatically-save-breakpoints-on-quit"><a class="header" href="#hook-to-automatically-save-breakpoints-on-quit">Hook to automatically save breakpoints on <code>quit</code></a></h2>
+<pre><code class="language-markdown">define break-save
+    save breakpoint $arg0.gdb.bp
+end
+define break-load
+    source $arg0.gdb.bp
+end
 
-# Children      Self  Command  Shared Object         Symbols
-# ........  ........  .......  ....................  .................
-#
-#  49.71%    49.66%   bench    bench                 [.] do_work
-#          |
-#           --49.66%--_start                &lt;- callstack bottom
-#                     __libc_start_main
-#                     0x7ff366c62ccf
-#                     main
-#                     |
-#                     |--25.13%--do_bar
-#                     |          do_work    &lt;- callstack top
-#                     |
-#                      --24.53%--do_foo
-#                                do_work
+define hook-quit
+    break-save quit
+end
+</code></pre>
+<h2 id="watchpoint-on-struct--class-member"><a class="header" href="#watchpoint-on-struct--class-member">Watchpoint on struct / class member</a></h2>
+<p>A symbolic watchpoint defined on a member variable for debugging is only valid
+as long as the expression is in scope. Once out of scope the watchpoint gets
+deleted.</p>
+<p>When debugging some memory corruption we want to keep the watchpoint even the
+expression goes out of scope to find the location that overrides the variable
+and introduces the corruption.</p>
+<pre><code class="language-markdown">(gdb) l
+1  struct S { int v; };
+2
+3  void set(struct S* s, int v) {
+4      s-&gt;v = v;
+5  }
+6
+7  int main() {
+8      struct S s;
+9      set(&amp;s, 1);
+10     set(&amp;s, 2);
+11     set(&amp;s, 3);
+...
 
-perf report --stdio -g graph,callee
+(gdb) s
+set (s=0x7fffffffe594, v=1) at test.c:4
+4    s-&gt;v = v;
 
-# Children      Self  Command  Shared Object         Symbols
-# ........  ........  .......  ....................  .................
-#
-#  49.71%    49.66%   bench    bench                 [.] do_work
-#          |
-#          ---do_work                       &lt;- callstack top
-#             |
-#             |--25.15%--do_bar
-#             |          main
-#             |          0x7ff366c62ccf
-#             |          __libc_start_main
-#             |          _start             &lt;- callstack bottom
-#             |
-#              --24.55%--do_foo
-#                        main
-#                        0x7ff366c62ccf
-#                        __libc_start_main
-#                        _start             &lt;- callstack bottom
-</code></pre>
-<h2 id="references-2"><a class="header" href="#references-2">References</a></h2>
-<ul>
-<li><a href="https://github.com/intel/perfmon">intel/perfmon</a> - intel PMU event database per uarch</li>
-<li><a href="https://perfmon-events.intel.com/">intel/perfmon-html</a> - a html rendered version of the PMU
-events with search</li>
-<li><a href="https://github.com/intel/perfmon/blob/main/mapfile.csv">intel/perfmon/mapfile.csv</a> - processor family to uarch mapping</li>
-<li><a href="https://github.com/torvalds/linux/tree/master/tools/perf/pmu-events/arch/x86">linux/perf/events</a> - x86 PMU events known to perf tools</li>
-<li><a href="https://github.com/torvalds/linux/blob/master/arch/x86/events/intel/core.c">linux/arch/events</a> - x86 PMU events linux kernel</li>
-<li><a href="https://en.wikichip.org/wiki/WikiChip">wikichip</a> - computer architecture wiki</li>
-<li><a href="https://man7.org/linux/man-pages/man1/perf-list.1.html">perf-list(1)</a> - manpage</li>
-<li><a href="https://man7.org/linux/man-pages/man2/perf_event_open.2.html">perf_event_open(2)</a> - manpage</li>
-<li><a href="https://www.intel.com/content/www/us/en/developer/articles/technical/intel-sdm.html">intel/sdm</a> - intel software developer manuals (eg Optimization
-Reference Manual)</li>
-</ul>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="oprofile"><a class="header" href="#oprofile"><a href="https://oprofile.sourceforge.io/">OProfile</a></a></h1>
-<pre><code class="language-markdown">operf -g -p &lt;pid&gt;
-  -g ...... caputre call-graph information
+# Define a new watchpoint on the member of the struct. The expression however
+# is only valid in the current functions scope.
 
-opreport [opt] FILE
-            show time spent per binary image
-  -l ...... show time spent per symbol
-  -c ...... show callgraph information (see below)
-  -a ...... add column with time spent accumulated over child nodes
+(gdb) watch s-&gt;v
+Hardware watchpoint 2: s-&gt;v
 
-ophelp      show supported hw/sw events
-</code></pre>
-<div style="break-before: page; page-break-before: always;"></div><h1 id="callgrind"><a class="header" href="#callgrind">callgrind</a></h1>
-<p>Callgrind is a tracing profiler to record the function call history of a target
-program. It is part of the <a href="https://valgrind.org/docs/manual/cl-manual.html">valgrind</a> tool suite.</p>
-<p>Profiling data is collected by instrumentation rather than sampling of the
-target program.</p>
-<p>Callgrind does not capture the actual time spent in a function but computes the
-cost of a function based on the instructions fetched (<code>Ir = Instruction read</code>).
-Therefore effects like slow IO are not reflected, which should be kept in mind
-when analyzing callgrind results.</p>
-<p>By default the profiler data is dumped when the target process is terminating,
-but <a href="https://valgrind.org/docs/manual/cl-manual.html#cl-manual.callgrind_control-options">callgrind_control</a> allows for interactive control of callgrind.</p>
-<pre><code class="language-bash"># Run a program under callgrind.
-valgrind --tool=callgrind -- &lt;prog&gt;
+(gdb) c
+Hardware watchpoint 2: s-&gt;v
+Old value = 0
+New value = 1
+set (s=0x7fffffffe594, v=1) at test.c:5
+5   }
 
-# Interactive control of callgrind.
-callgrind_control [opts]
-  opts:
-    -b ............. show current backtrace
-    -e ............. show current event counters
-    -s ............. show current stats
-    --dump[=file] .. dump current collection
-    -i=on|off ...... turn instrumentation on|off
+# The watchpoint gets deleted as soon as we leave the function scope.
+
+(gdb) c
+Watchpoint 2 deleted because the program has left the block in
+which its expression is valid.
+main () at test.c:10
+10      set(&amp;s, 2);
+
+# Define the watchpoint on the location of the object to watch.
+
+(gdb) watch -l s-&gt;v
+
+# This is equivalent to the following.
+
+(gdb) p &amp;s-&gt;v
+$1 = (int *) 0x7fffffffe594
+
+# Define a watchpoint to the address of the member variable of the s instance.
+# This of course only makes sense as long as the s instance is not moved in memory.
+
+(gdb) watch *0x7fffffffe594
+Hardware watchpoint 3: *0x7fffffffe594
+
+(gdb) c
+Hardware watchpoint 3: *0x7fffffffe594
+Old value = 1
+New value = 2
+set (s=0x7fffffffe594, v=2) at test.c:5
+5   }
+
+(gdb) c
+Hardware watchpoint 3: *0x7fffffffe594
+Old value = 2
+New value = 3
+set (s=0x7fffffffe594, v=3) at test.c:5
+5   }
 </code></pre>
-<p>Results can be analyzed by using one of the following tools</p>
-<ul>
-<li><a href="https://valgrind.org/docs/manual/cl-manual.html#cl-manual.callgrind_annotate-options">callgrind_annotate</a> (cli)</li>
-<li><a href="https://kcachegrind.github.io/html/Home.html">kcachegrind</a> (ui)</li>
-</ul>
-<p>The following is a collection of frequently used callgrind options.</p>
-<pre><code class="language-bash">valgrind --tool=callgrind [opts] -- &lt;prog&gt;
-  opts:
-    --callgrind-out-file=&lt;file&gt; .... output file, rather than callgrind.out.&lt;pid&gt;
-    --dump-instr=&lt;yes|no&gt; .......... annotation on instrucion level,
-                                     allows for asm annotations
+<h2 id="shell-commands-1"><a class="header" href="#shell-commands-1">Shell commands</a></h2>
+<pre><code class="language-markdown"># Run shell commands.
 
-    --instr-atstart=&lt;yes|no&gt; ....... control if instrumentation is enabled from 
-                                     beginning of the program
+(gdb) shell zcat /proc/config.gz | grep CONFIG_KVM=
+CONFIG_KVM=m
 
-    --separate-threads=&lt;yes|no&gt; .... create separate output files per thread,
-                                     appends -&lt;thread_id&gt; to the output file
+# Pipe gdb command to shell command.
+
+(gdb) pipe info proc mapping | grep libc
+    0x7ffff7a1a000     0x7ffff7a42000    0x28000        0x0  r--p   /usr/lib/libc.so.6
+    0x7ffff7a42000     0x7ffff7b9d000   0x15b000    0x28000  r-xp   /usr/lib/libc.so.6
+    0x7ffff7b9d000     0x7ffff7bf2000    0x55000   0x183000  r--p   /usr/lib/libc.so.6
+    0x7ffff7bf2000     0x7ffff7bf6000     0x4000   0x1d7000  r--p   /usr/lib/libc.so.6
+    0x7ffff7bf6000     0x7ffff7bf8000     0x2000   0x1db000  rw-p   /usr/lib/libc.so.6
 </code></pre>
-<h2 id="profile-specific-part-of-the-target"><a class="header" href="#profile-specific-part-of-the-target">Profile specific part of the target</a></h2>
-<p>Programmatically enable/disable instrumentation using the macros defined in
-the callgrind header.</p>
-<pre><code class="language-c">#include &lt;valgrind/callgrind.h&gt;
+<h1 id="know-bugs"><a class="header" href="#know-bugs">Know Bugs</a></h1>
+<h2 id="workaround-command--finish-bug"><a class="header" href="#workaround-command--finish-bug">Workaround <code>command + finish</code> bug</a></h2>
+<p>When using <code>finish</code> inside a <code>command</code> block, commands after <code>finish</code> are not
+executed. To workaround that bug one can create a wrapper function which calls
+<code>finish</code>.</p>
+<pre><code class="language-markdown">  define handler
+    bt
+    finish
+    info reg rax
+  end
 
-int main() {
-    // init ..
+  command
+    handler
+  end
+</code></pre>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="gdbserver1"><a class="header" href="#gdbserver1">gdbserver(1)</a></h1>
+<h1 id="cli-1"><a class="header" href="#cli-1">CLI</a></h1>
+<pre><code class="language-markdown">  gdbserver [opts] comm prog [args]
+    opts:
+      --disable-randomization
+      --no-disable-randomization
+      --wrapper W --
 
-    CALLGRIND_START_INSTRUMENTATION;
-    compute();
-    CALLGRIND_STOP_INSTRUMENTATION;
+    comm:
+      host:port
+      tty
+</code></pre>
+<h2 id="example-5"><a class="header" href="#example-5">Example</a></h2>
+<pre><code class="language-markdown"># Start gdbserver.
+gdbserver localhost:1234 /bin/ls
 
-    // shutdown ..
-}
+# Attach gdb.
+gdb -ex 'target remote localhost:1234'
+</code></pre>
+<h2 id="wrapper-example-set-environment-variables-just-for-the-debugee"><a class="header" href="#wrapper-example-set-environment-variables-just-for-the-debugee">Wrapper example: Set environment variables just for the debugee</a></h2>
+<p>Set <code>env</code> as execution wrapper with some variables.
+The wrapper will be executed before the debugee.</p>
+<pre><code class="language-markdown">gdbserver --wrapper env FOO=123 BAR=321 -- :12345 /bin/ls
 </code></pre>
-<blockquote>
-<p>In this case, callgrind should be launched with <code>--instr-atstart=no</code>.</p>
-</blockquote>
-<p>Alternatively instrumentation can be controlled with <code>callgrind_control -i on/off</code>.</p>
-<p>The files <a href="trace_profile/callgrind/cg_example.cc">cg_example.cc</a> and
-<a href="trace_profile/callgrind/Makefile">Makefile</a> provide a full example.</p>
 <div style="break-before: page; page-break-before: always;"></div><h1 id="binary"><a class="header" href="#binary">Binary</a></h1>
 <ul>
 <li><a href="binary/./od.html">od</a></li>
@@ -3522,6 +3368,7 @@ objdump -C --disassemble=foo::bar &lt;bin&gt;
 <li><a href="development/./c++.html">c++</a></li>
 <li><a href="development/./glibc.html">glibc</a></li>
 <li><a href="development/./gcc.html">gcc</a></li>
+<li><a href="development/./git.html">git</a></li>
 <li><a href="development/./cmake.html">cmake</a></li>
 <li><a href="development/./make.html">make</a></li>
 <li><a href="development/./ld.so.html">ld.so</a></li>
@@ -4576,6 +4423,205 @@ run1:
 <li>C ABI (x86_64) - <a href="https://gitlab.com/x86-psABIs/x86-64-ABI">SystemV ABI</a></li>
 <li>C++ ABI - <a href="https://itanium-cxx-abi.github.io/cxx-abi">C++ Itanium ABI</a></li>
 </ul>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="git1"><a class="header" href="#git1">git(1)</a></h1>
+<h2 id="working-areas"><a class="header" href="#working-areas">Working areas</a></h2>
+<pre><code class="language-text">+-------------------+ --- stash -----&gt; +-------+
+| working directory |                  | stash |  // Shelving area.
++-------------------+ &lt;-- stash pop -- +-------+
+      |       ^
+     add      |
+      |     reset
+      v       |
++-------------------+
+|   staging area    |
++-------------------+
+      |
+    commit
+      |
+      v
++-------------------+
+| local repository  |
++-------------------+
+      |       ^
+     push     |
+      |     fetch /
+      |      pull
+      v       |
++-------------------+
+| remote repository |
++-------------------+
+</code></pre>
+<h2 id="config"><a class="header" href="#config">Config</a></h2>
+<pre><code class="language-markdown">  git config --list --show-origin ..... list currently set configs and where
+                                        they are coming from
+  git --edit [--global] ............... open config in editor (local or global)
+</code></pre>
+<h2 id="clean"><a class="header" href="#clean">Clean</a></h2>
+<pre><code class="language-markdown">  git clean -X ......... remove only ignored files (-n for dry run)
+  git clean -f -d -x ... remove untracked &amp; ignored files / folders
+  git clean -e &lt;pat&gt; ... exclude pattern from deletion
+</code></pre>
+<h2 id="staging"><a class="header" href="#staging">Staging</a></h2>
+<pre><code class="language-markdown">  git add -p [&lt;file&gt;] ............ partial staging (interactive)
+</code></pre>
+<h2 id="remote"><a class="header" href="#remote">Remote</a></h2>
+<pre><code class="language-markdown">  git remote -v .................. list remotes verbose (with URLs)
+  git remote show [-n] &lt;remote&gt; .. list info for &lt;remote&gt; (like remote HEAD,
+                                   remote branches, tracking mapping)
+</code></pre>
+<h2 id="branching"><a class="header" href="#branching">Branching</a></h2>
+<pre><code class="language-markdown">  git branch [-a] ................ list available branches; -a to include
+                                   remote branches
+  git branch -vv ................. list branch &amp; annotate with head sha1 &amp;
+                                   remote tracking branch
+  git branch &lt;bname&gt; ............. create local branch with name &lt;bname&gt;
+  git branch -d &lt;bname&gt; .......... delete local branch with name &lt;bname&gt;
+  git checkout &lt;bname&gt; ........... switch to branch with name &lt;bname&gt;
+  git checkout --track &lt;branch&gt; .. start to locally track a remote branch
+  git branch --unset-upstream .... unset remote tracking branch
+
+  # Remote
+
+  git push -u origin &lt;rbname&gt; ........ push local branch to origin (or other
+                                       remote), and setup &lt;rbname&gt; as tracking
+                                       branch
+  git push origin --delete &lt;rbname&gt; .. delete branch &lt;rbname&gt; from origin (or
+                                       other remote)
+</code></pre>
+<h2 id="update-local-from-remote"><a class="header" href="#update-local-from-remote">Update local from remote</a></h2>
+<pre><code class="language-markdown">  git fetch --prune .................. update all remote references and
+                                       remove delete non-existing ones
+                                       (does not merge into local tracking branch)
+  git pull [--rebase] ................ fetch remote references and merge into
+                                       local tracking branch (fast-forward by default).
+                                       Optionally rebase local tracking branch
+                                       on-top of remote branch (in case local
+                                       branch has additional commits compared to remote branch).
+</code></pre>
+<h2 id="tags-1"><a class="header" href="#tags-1">Tags</a></h2>
+<pre><code class="language-markdown">  git tag -a &lt;tname&gt; -m "descr" ........ creates an annotated tag (full object
+                                         containing tagger, date, ...)
+  git tag -l ........................... list available tags
+  git checkout tag/&lt;tname&gt; ............. checkout specific tag
+  git checkout tag/&lt;tname&gt; -b &lt;bname&gt; .. checkout specific tag in a new branch
+
+  # Remote
+
+  git push origin --tags .... push local tags to origin (or other remote)
+</code></pre>
+<h2 id="merging"><a class="header" href="#merging">Merging</a></h2>
+<pre><code class="language-markdown">  git merge [opt] &lt;commit&gt; .... integrate changes from &lt;commit&gt; since
+    opt:                        current branch and &lt;commit&gt; diverged
+      --squash ................ merge all commits into a single one
+      --no-commit ............. dont generate commit if the merge succeeds
+
+  git merge-base &lt;commit&gt; &lt;commit&gt;
+                                get the common ancestor, since both commits diverged
+
+  git rebase -i &lt;upstream&gt; .... interactively rebase on &lt;upstream&gt;, also supports actions
+                                like squashing, editing, rewording, etc of commits
+
+  git cherry-pick &lt;commit&gt; .... apply commit on current branch
+</code></pre>
+<h2 id="worktree"><a class="header" href="#worktree">Worktree</a></h2>
+<p>Worktrees allow to maintain multiple working trees in the filesystem linked to
+the same repository (shared .git folder).</p>
+<pre><code class="language-markdown">  git worktree add &lt;path&gt; .............. create a tree at &lt;path&gt; with a new branch
+                                         checked out (bname is basename of &lt;path&gt;)
+  git worktree add &lt;path&gt; &lt;bname&gt; ...... create a tree at &lt;path&gt; from existing &lt;bname&gt;
+  git worktree list .................... list existing work trees
+  git worktree remove &lt;tree&gt; ........... remove work tree
+  git worktree prune ................... remove stale bookkeeping files
+</code></pre>
+<h2 id="log--commit-history"><a class="header" href="#log--commit-history">Log &amp; Commit History</a></h2>
+<pre><code class="language-markdown">  git log --oneline ......... shows log in single line per commit -&gt; alias for
+                              '--pretty=oneline --abbrev-commit'
+  git log --graph ........... text based graph of commit history
+  git log --decorate ........ decorate log with REFs
+
+  git log -p &lt;file&gt; ......... show commit history + diffs for &lt;file&gt;
+  git log --oneline &lt;file&gt; .. show commit history for &lt;file&gt; in compact format
+</code></pre>
+<h2 id="diff--commit-info"><a class="header" href="#diff--commit-info">Diff &amp; Commit Info</a></h2>
+<pre><code class="language-markdown">  git diff &lt;commit&gt;..&lt;commit&gt; [&lt;file&gt;] .... show changes between two arbitrary
+                                            commits. If one &lt;commit&gt; is omitted
+                                            it is if HEAD is specified.
+  git diff --name-only &lt;commit&gt;..&lt;commit&gt; . show names of files changed
+  git diff -U$(wc -l &lt;file&gt;) &lt;file&gt; ....... shows complete file with diffs
+                                            instead of usual diff snippets
+  git diff --staged ....................... show diffs of staged files
+
+  git show --stat &lt;commit&gt; ................ show files changed by &lt;commit&gt;
+  git show &lt;commit&gt; [&lt;file&gt;] .............. show diffs for &lt;commit&gt;
+
+  git show &lt;commit&gt;:&lt;file&gt; ................ show &lt;file&gt; at &lt;commit&gt;
+</code></pre>
+<h2 id="patching"><a class="header" href="#patching">Patching</a></h2>
+<pre><code class="language-markdown">  git format-patch &lt;opt&gt; &lt;since&gt;/&lt;revision range&gt;
+    opt:
+      -N ................... use [PATCH] instead [PATCH n/m] in subject when
+                             generating patch description (for patches spanning
+                             multiple commits)
+      --start-number &lt;n&gt; ... start output file generation with &lt;n&gt; as start
+                             number instead '1'
+    since spcifier:
+      -3 .................. e.g: create a patch from last three commits
+      &lt;commit hash&gt; ....... create patch with commits starting after &lt;commit hash&gt;
+
+  git am &lt;patch&gt; ......... apply patch and create a commit for it
+
+  git apply --stat &lt;PATCH&gt; ... see which files the patch would change
+  git apply --check &lt;PATCH&gt; .. see if the patch can be applied cleanly
+  git apply [-3] &lt;PATCH&gt; ..... apply the patch locally without creating a commit,
+                               if the patch does not cleanly apply -3 allows for
+                               a 3-way merge
+
+  # eg: generate patches for each commit from initial commit on
+  git format-patch -N $(git rev-list --max-parents=0 HEAD)
+
+  # generate single patch file from a certain commit/ref
+  git format-patch &lt;COMMIT/REF&gt; --stdout &gt; my-patch.patch
+</code></pre>
+<h2 id="resetting"><a class="header" href="#resetting">Resetting</a></h2>
+<pre><code class="language-markdown">  git reset [opt] &lt;ref|commit&gt;
+    opt:
+      --mixed .................... resets index, but not working tree
+      --hard ..................... matches the working tree and index to that
+                                   of the tree being switched to any changes to
+                                   tracked files in the working tree since
+                                   &lt;commit&gt; are lost
+  git reset HEAD &lt;file&gt; .......... remove file from staging
+  git reset --soft HEAD~1 ........ delete most recent commit but keep work
+  git reset --hard HEAD~1 ........ delete most recent commit and delete work
+</code></pre>
+<h2 id="submodules"><a class="header" href="#submodules">Submodules</a></h2>
+<pre><code class="language-markdown">  git submodule add &lt;url&gt; [&lt;path&gt;] .......... add new submodule to current project
+  git clone --recursive &lt;url&gt; ............... clone project and recursively all
+                                              submodules (same as using
+                                              'git submodule update --init
+                                              --recursive' after clone)
+  git submodule update --init --recursive ... checkout submodules recursively
+                                              using the commit listed in the
+                                              super-project (in detached HEAD)
+  git submodule update --remote &lt;submod&gt; .... fetch &amp; merge remote changes for
+                                              &lt;submod&gt;, this will pull
+                                              origin/HEAD or a branch specified
+                                              for the submodule
+  git diff --submodule ...................... show commits that are part of the
+                                              submodule diff
+</code></pre>
+<h2 id="inspection-1"><a class="header" href="#inspection-1">Inspection</a></h2>
+<pre><code class="language-markdown">  git ls-tree [-r] &lt;ref&gt; .... show git tree for &lt;ref&gt;, -r to recursively ls sub-trees
+  git show &lt;obj&gt; ............ show &lt;obj&gt;
+  git cat-file -p &lt;obj&gt; ..... print content of &lt;obj&gt;
+</code></pre>
+<h2 id="revision-specifier"><a class="header" href="#revision-specifier">Revision Specifier</a></h2>
+<pre><code class="language-markdown">  HEAD ........ last commit
+  HEAD~1 ...... last commit-1
+  HEAD~N ...... last commit-N (linear backwards when in tree structure, check
+                difference between HEAD^ and HEAD~)
+  git rev-list --max-parents=0 HEAD ........... first commit
+</code></pre>
 <div style="break-before: page; page-break-before: always;"></div><h1 id="cmake1"><a class="header" href="#cmake1">cmake(1)</a></h1>
 <h2 id="frequently-used-variables"><a class="header" href="#frequently-used-variables">Frequently used variables</a></h2>
 <pre><code># Install location.
@@ -5285,7 +5331,7 @@ func_v0
 func_v1
 func_v2
 </code></pre>
-<h2 id="references-3"><a class="header" href="#references-3">References</a></h2>
+<h2 id="references-4"><a class="header" href="#references-4">References</a></h2>
 <ul>
 <li><a href="https://akkadia.org/drepper/symbol-versioning">ELF Symbol Versioning</a></li>
 <li><a href="https://sourceware.org/binutils/docs/ld/VERSION.html">Binutils ld: Symbol Versioning</a></li>
@@ -5687,7 +5733,7 @@ journalctl --user -u test -n 5
     --disk-usage            Show current disk usage
     --vacuum-size=&lt;size&gt;    Reduce journal log to &lt;size&gt; (K/M/G)
 </code></pre>
-<h2 id="references-4"><a class="header" href="#references-4">References</a></h2>
+<h2 id="references-5"><a class="header" href="#references-5">References</a></h2>
 <ul>
 <li><a href="https://www.man7.org/linux/man-pages/man5/systemd.unit.5.html">man systemd.unit(5)</a></li>
 <li><a href="https://www.man7.org/linux/man-pages/man5/systemd.service.5.html">man systemd.service(5)</a></li>
@@ -6070,7 +6116,7 @@ group::r-x
 mask::r-x
 other::rwx
 </code></pre>
-<h2 id="references-5"><a class="header" href="#references-5">References</a></h2>
+<h2 id="references-6"><a class="header" href="#references-6">References</a></h2>
 <ul>
 <li><a href="https://www.man7.org/linux/man-pages/man5/acl.5.html">acl(5)</a></li>
 <li><a href="https://www.man7.org/linux/man-pages/man1/getfacl.1.html">getfacl(1)</a></li>
@@ -6301,6 +6347,33 @@ cache.</p>
 <li><a href="network/./firewall-cmd.html">firewall-cmd</a></li>
 <li><a href="network/./nftables.html">nftables</a></li>
 </ul>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="ss8"><a class="header" href="#ss8">ss(8)</a></h1>
+<pre><code class="language-markdown">ss [option] [filter]
+</code></pre>
+<pre><code class="language-markdown">[option]
+  -p ..... Show process using socket
+  -l ..... Show sockets in listening state
+  -4/-6 .. Show IPv4/6 sockets
+  -x ..... Show unix sockets
+  -n ..... Show numeric ports (no resolve)
+  -O ..... Oneline output per socket
+</code></pre>
+<pre><code class="language-markdown">[filter]
+  dport/sport PORT .... Filter for destination/source port
+  dst/src ADDR ........ Filter for destination/source address
+
+  and/or .............. Logic operator
+  ==/!= ............... Comparison operator
+
+  (EXPR) .............. Group exprs
+</code></pre>
+<h1 id="examples-12"><a class="header" href="#examples-12">Examples</a></h1>
+<p>Show all tcp IPv4 sockets connecting to port <code>443</code>:</p>
+<pre><code class="language-markdown">ss -4 'dport 443'
+</code></pre>
+<p>Show all tcp IPv4 sockets that don't connect to port <code>443</code> or connect to address <code>1.2.3.4</code>.</p>
+<pre><code class="language-markdown">ss -4 'dport != 443 or dst 1.2.3.4'
+</code></pre>
 <div style="break-before: page; page-break-before: always;"></div><h1 id="tcpdump1"><a class="header" href="#tcpdump1">tcpdump(1)</a></h1>
 <h1 id="cli-3"><a class="header" href="#cli-3">CLI</a></h1>
 <pre><code class="language-markdown">tcpdump [opts] -i &lt;if&gt; [&lt;filter&gt;]
@@ -6319,7 +6392,7 @@ tcp/udp/icmp            Filter for protocol.
 <blockquote>
 <p>Use <code>and/or/not</code> and <code>()</code> to build filter expressions.</p>
 </blockquote>
-<h1 id="examples-12"><a class="header" href="#examples-12">Examples</a></h1>
+<h1 id="examples-13"><a class="header" href="#examples-13">Examples</a></h1>
 <h2 id="capture-packets-from-remote-host"><a class="header" href="#capture-packets-from-remote-host">Capture packets from remote host</a></h2>
 <pre><code class="language-makrdown"># -k: Start capturing immediately.
 ssh &lt;host&gt; tcpdump -i any -w - | sudo wireshark -k -i -
@@ -6351,7 +6424,7 @@ tcp/udp/ssh/wg/...             Filter for protocol.
 <blockquote>
 <p>Use <code>tshak -G</code> to list all fields that can be used in display filters.</p>
 </blockquote>
-<h1 id="examples-13"><a class="header" href="#examples-13">Examples</a></h1>
+<h1 id="examples-14"><a class="header" href="#examples-14">Examples</a></h1>
 <h2 id="capture-and-filter-packet-to-file"><a class="header" href="#capture-and-filter-packet-to-file">Capture and filter packet to file</a></h2>
 <pre><code class="language-bash"># Capture TCP traffic with port 80 on interface eth0 to file.
 sudo tshark -i eht0 -f 'tcp and port 80' -w tx.pcap
@@ -6393,7 +6466,7 @@ firewall-cmd --remove-port 8000/tcp
 # Remove rich rule.
 firewall-cmd --remove-rich-rule 'rule family="ipv4" forward-port port="80" protocol="tcp" to-port="8080"'
 </code></pre>
-<h2 id="references-6"><a class="header" href="#references-6">References</a></h2>
+<h2 id="references-7"><a class="header" href="#references-7">References</a></h2>
 <ul>
 <li>man <a href="https://firewalld.org/documentation/man-pages/firewall-cmd.html">firewall-cmd(1)</a></li>
 <li>man <a href="https://firewalld.org/documentation/man-pages/firewalld.html">firewalld(1)</a></li>
@@ -7012,6 +7085,7 @@ const chart = new Chart(
 <div style="break-before: page; page-break-before: always;"></div><h1 id="arch"><a class="header" href="#arch">Arch</a></h1>
 <ul>
 <li><a href="arch/./x86_64.html">x86_64</a></li>
+<li><a href="arch/./armv8.html">armv8</a></li>
 <li><a href="arch/./arm64.html">arm64</a></li>
 <li><a href="arch/./armv7.html">armv7</a></li>
 <li><a href="arch/./riscv.html">riscv</a></li>
@@ -7337,7 +7411,7 @@ greeting_len:
 <pre><code class="language-bash">&gt; gcc -o greet greet.s -nostartfiles -nostdlib &amp;&amp; ./greet
 Hi ASM-World!
 </code></pre>
-<h2 id="references-7"><a class="header" href="#references-7">References</a></h2>
+<h2 id="references-8"><a class="header" href="#references-8">References</a></h2>
 <ul>
 <li><a href="https://gitlab.com/x86-psABIs/x86-64-ABI">SystemV AMD64 ABI</a></li>
 <li><a href="https://www.amd.com/system/files/TechDocs/24592.pdf">AMD64 Vol1: Application Programming</a></li>
@@ -7352,7 +7426,50 @@ Hi ASM-World!
 <li><a href="https://sourceware.org/binutils/docs/as/i386_002dDependent.html">GNU Assembler <code>x86_64</code> dependent features</a></li>
 <li><a href="https://github.com/johannst/juicebox-asm"><code>juicebox-asm</code> an <code>x86_64</code> jit assembler playground</a></li>
 </ul>
+<div style="break-before: page; page-break-before: always;"></div><h1 id="armv8"><a class="header" href="#armv8">armv8</a></h1>
+<p>keywords: aarch64, arm64, A64, aarch32, A32, T32, abi</p>
+<p>The <code>armv8</code> architecture introduces support for 64-bit and defines two
+<em>execution states</em> <code>aarch64</code> and <code>aarch32</code>.</p>
+<p>Implementations are <strong>not</strong> required to implement all execution states for all
+<em>exception levels (EL)</em>. For example the <a href="https://en.wikichip.org/wiki/arm_holdings/microarchitectures/cortex-a32">coretex-a32</a> only
+implements <code>aarch32</code>, while  the <a href="https://en.wikichip.org/wiki/arm_holdings/microarchitectures/cortex-a34">coretex-a34</a> only implements
+<code>aarch64</code>.</p>
+<p>The execution states support different instruction sets.</p>
+<ul>
+<li><code>aarch64</code> only supports the new <a href="https://developer.arm.com/documentation/ddi0602/latest"><code>A64</code></a> instruction set, where all
+instructions have the fixed size of of 32 bits.</li>
+<li><code>aarch32</code> supports the <a href="https://developer.arm.com/documentation/ddi0597/latest"><code>A32</code></a> and <a href="https://developer.arm.com/documentation/ddi0597/latest"><code>T32</code></a> instruction sets. These
+are updated versions of the <code>armv7</code> instruction sets, kept backwards
+compatible allowing <code>armv7</code> programs to run on <code>armv8</code>.
+<blockquote>
+<p>In <code>armv7</code> the instruction sets <code>A32</code> an <code>T32</code> were called <code>arm</code> and
+<code>thumb</code> respectively.</p>
+</blockquote>
+</li>
+</ul>
+<p>A <em>program</em> always runs in either the <code>aarch64</code> or the <code>aarch32</code> execution
+state, but never in a <em>mixture</em> of both. Transitions between execution states
+only occur when raising or lowering the exception level.</p>
+<ul>
+<li><code>aarch64 -&gt; aarch32</code> can only occur when switching from <em>higher EL</em> to <em>lower
+EL</em>.</li>
+<li><code>aarch32 -&gt; aarch64</code> can only occur when switching from <em>lower EL</em> to <em>higher
+EL</em>.</li>
+</ul>
+<p>The following figure depicts which execution state Transitions are allowed.</p>
+<pre><code>      (user) EL0     ^       |
+        (os) EL1     |    32-&gt;64
+(hypervisor) EL2  64-&gt;32     |
+    (secure) EL3     |       v
+</code></pre>
+<p>This means for example, an <em>os</em> running in <code>aarch32</code> can only support <code>aarch32</code>
+user applications, while an <em>os</em> running in <code>aarch64</code> can support
+<code>aarch32 / aarch64</code> user applications.</p>
 <div style="break-before: page; page-break-before: always;"></div><h1 id="arm64"><a class="header" href="#arm64">arm64</a></h1>
+<blockquote>
+<p>This page only talks about the 64 bit part of the <code>armv8</code> architecture. For
+an overview see <a href="arch/./armv8.html"><code>armv8</code></a>.</p>
+</blockquote>
 <p>keywords: arm64, aarch64, abi</p>
 <ul>
 <li>64bit synonyms: <code>arm64</code>, <code>aarch64</code></li>
@@ -7567,7 +7684,7 @@ Hi ASM-World!
 distributions. Explicitly specifying the dynamic linker should not be
 required when compiling natively on arm64.</p>
 </blockquote>
-<h2 id="references-8"><a class="header" href="#references-8">References</a></h2>
+<h2 id="references-9"><a class="header" href="#references-9">References</a></h2>
 <ul>
 <li><a href="https://github.com/ARM-software/abi-aa/blob/master/aapcs64/aapcs64.rst">Procedure Call Standard ARM64</a></li>
 <li><a href="https://developer.arm.com/documentation/den0024/latest">ARMv8-A Programmer's Guide</a></li>
@@ -7812,7 +7929,7 @@ Hi ASM-World!
 distributions. Explicitly specifying the dynamic linker should not be
 required when compiling natively on arm.</p>
 </blockquote>
-<h2 id="references-9"><a class="header" href="#references-9">References</a></h2>
+<h2 id="references-10"><a class="header" href="#references-10">References</a></h2>
 <ul>
 <li><a href="https://github.com/ARM-software/abi-aa/blob/master/aapcs32/aapcs32.rst">Procedure Call Standard ARM</a></li>
 <li><a href="https://developer.arm.com/documentation/den0013/latest">ARMv7-A Programmer's Guide</a></li>
@@ -7893,7 +8010,7 @@ distributions. Explicitly specifying the dynamic linker should not be
 required when compiling natively on riscv.</p>
 <p>Select dynamic linker according to abi used during compile &amp; link.</p>
 </blockquote>
-<h2 id="references-10"><a class="header" href="#references-10">References</a></h2>
+<h2 id="references-11"><a class="header" href="#references-11">References</a></h2>
 <ul>
 <li><a href="https://sourceware.org/binutils/docs/as">GNU Assembler</a></li>
 <li><a href="https://sourceware.org/binutils/docs/as/Pseudo-Ops.html#Pseudo-Ops">GNU Assembler Directives</a></li>
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