<!DOCTYPE HTML> <html lang="en" class="light" dir="ltr"> <head> <!-- Book generated using mdBook --> <meta charset="UTF-8"> <title>Introduction - Notes</title> <!-- Custom HTML head --> <meta name="description" content=""> <meta name="viewport" content="width=device-width, initial-scale=1"> <meta name="theme-color" content="#ffffff"> <link rel="icon" href="favicon.svg"> <link rel="shortcut icon" href="favicon.png"> <link rel="stylesheet" href="css/variables.css"> <link rel="stylesheet" href="css/general.css"> <link rel="stylesheet" href="css/chrome.css"> <link rel="stylesheet" href="css/print.css" media="print"> <!-- Fonts --> <link rel="stylesheet" href="FontAwesome/css/font-awesome.css"> <link rel="stylesheet" href="fonts/fonts.css"> <!-- Highlight.js Stylesheets --> <link rel="stylesheet" href="highlight.css"> <link rel="stylesheet" href="tomorrow-night.css"> <link rel="stylesheet" href="ayu-highlight.css"> <!-- Custom theme stylesheets --> </head> <body class="sidebar-visible no-js"> <div id="body-container"> <!-- Provide site root to javascript --> <script> var path_to_root = ""; var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? 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class="hidden"> <!-- Hide / unhide sidebar before it is displayed --> <script> var body = document.querySelector('body'); var sidebar = null; var sidebar_toggle = document.getElementById("sidebar-toggle-anchor"); if (document.body.clientWidth >= 1080) { try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { } sidebar = sidebar || 'visible'; } else { sidebar = 'hidden'; } sidebar_toggle.checked = sidebar === 'visible'; body.classList.remove('sidebar-visible'); body.classList.add("sidebar-" + sidebar); </script> <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" class="active">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><li class="chapter-item expanded "><a href="cli/tac.html"><strong aria-hidden="true">2.6.</strong> tac</a></li><li class="chapter-item expanded "><a href="cli/paste.html"><strong aria-hidden="true">2.7.</strong> paste</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><li class="chapter-item expanded "><a href="tools/qrencode.html"><strong aria-hidden="true">3.11.</strong> qrencode</a></li></ol></li><li class="chapter-item expanded "><a href="process/index.html"><strong aria-hidden="true">4.</strong> Process management & inspection</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="process/lsof.html"><strong aria-hidden="true">4.1.</strong> lsof</a></li><li class="chapter-item expanded "><a href="process/pidstat.html"><strong aria-hidden="true">4.2.</strong> pidstat</a></li><li class="chapter-item expanded "><a href="process/pgrep.html"><strong aria-hidden="true">4.3.</strong> pgrep</a></li><li class="chapter-item expanded "><a href="process/ps.html"><strong aria-hidden="true">4.4.</strong> ps</a></li><li class="chapter-item expanded "><a href="process/pmap.html"><strong aria-hidden="true">4.5.</strong> pmap</a></li><li class="chapter-item expanded "><a href="process/pstack.html"><strong aria-hidden="true">4.6.</strong> pstack</a></li><li class="chapter-item expanded "><a href="process/taskset.html"><strong aria-hidden="true">4.7.</strong> taskset</a></li><li class="chapter-item expanded "><a href="process/nice.html"><strong aria-hidden="true">4.8.</strong> nice</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><li class="chapter-item expanded "><a href="linux/cpufreq.html"><strong aria-hidden="true">9.9.</strong> cpufreq</a></li><li class="chapter-item expanded "><a href="linux/cups.html"><strong aria-hidden="true">9.10.</strong> cups</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/ssh.html"><strong aria-hidden="true">10.1.</strong> ssh</a></li><li class="chapter-item expanded "><a href="network/ss.html"><strong aria-hidden="true">10.2.</strong> ss</a></li><li class="chapter-item expanded "><a href="network/tcpdump.html"><strong aria-hidden="true">10.3.</strong> tcpdump</a></li><li class="chapter-item expanded "><a href="network/tshark.html"><strong aria-hidden="true">10.4.</strong> tshark</a></li><li class="chapter-item expanded "><a href="network/firewall-cmd.html"><strong aria-hidden="true">10.5.</strong> firewall-cmd</a></li><li class="chapter-item expanded "><a href="network/nftables.html"><strong aria-hidden="true">10.6.</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> </div> </nav> <!-- Track and set sidebar scroll position --> <script> var sidebarScrollbox = document.querySelector('#sidebar .sidebar-scrollbox'); sidebarScrollbox.addEventListener('click', function(e) { if (e.target.tagName === 'A') { sessionStorage.setItem('sidebar-scroll', sidebarScrollbox.scrollTop); } }, { passive: true }); var sidebarScrollTop = sessionStorage.getItem('sidebar-scroll'); sessionStorage.removeItem('sidebar-scroll'); if (sidebarScrollTop) { // preserve sidebar scroll position when navigating via links within sidebar sidebarScrollbox.scrollTop = sidebarScrollTop; } else { // scroll sidebar to current active section when navigating via "next/previous chapter" buttons var activeSection = document.querySelector('#sidebar .active'); if (activeSection) { activeSection.scrollIntoView({ block: 'center' }); } } </script> <div id="page-wrapper" class="page-wrapper"> <div class="page"> <div id="menu-bar-hover-placeholder"></div> <div id="menu-bar" class="menu-bar sticky"> <div class="left-buttons"> <label id="sidebar-toggle" class="icon-button" for="sidebar-toggle-anchor" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar"> <i class="fa fa-bars"></i> </label> <button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list"> <i class="fa fa-paint-brush"></i> </button> <ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu"> <li role="none"><button role="menuitem" class="theme" id="light">Light</button></li> <li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li> <li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li> <li role="none"><button role="menuitem" class="theme" 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(Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar"> <i class="fa fa-search"></i> </button> </div> <h1 class="menu-title">Notes</h1> <div class="right-buttons"> <a href="print.html" title="Print this book" aria-label="Print this book"> <i id="print-button" class="fa fa-print"></i> </a> <a href="https://github.com/johannst/notes" title="Git repository" aria-label="Git repository"> <i id="git-repository-button" class="fa fa-github"></i> </a> </div> </div> <div id="search-wrapper" class="hidden"> <form id="searchbar-outer" class="searchbar-outer"> <input type="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header"> </form> <div id="searchresults-outer" class="searchresults-outer hidden"> <div id="searchresults-header" class="searchresults-header"></div> <ul id="searchresults"> </ul> </div> </div> <!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM --> <script> document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible'); document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible'); Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) { link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1); }); </script> <div id="content" class="content"> <main> <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> </main> <nav class="nav-wrapper" aria-label="Page navigation"> <!-- Mobile navigation buttons --> <a rel="next prefetch" href="shells/index.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right"> <i class="fa fa-angle-right"></i> </a> <div style="clear: both"></div> </nav> </div> </div> <nav class="nav-wide-wrapper" aria-label="Page navigation"> <a rel="next prefetch" href="shells/index.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right"> <i class="fa fa-angle-right"></i> </a> </nav> </div> <script> window.playground_copyable = true; </script> <script src="elasticlunr.min.js"></script> <script src="mark.min.js"></script> <script src="searcher.js"></script> <script src="clipboard.min.js"></script> <script src="highlight.js"></script> <script src="book.js"></script> <!-- Custom JS scripts --> </div> </body> </html>