diff options
| author | johannst <johannst@users.noreply.github.com> | 2024-05-01 17:39:45 +0000 |
|---|---|---|
| committer | johannst <johannst@users.noreply.github.com> | 2024-05-01 17:39:45 +0000 |
| commit | 21a13652df728c9571f899caf4949d5d46f49db7 (patch) | |
| tree | dcd723453f6405c53a162da4c95896f5768f13d2 /tools/awk.html | |
| parent | 269caa8ae18eb33e1286e4c21d434ea07228a619 (diff) | |
| download | notes-21a13652df728c9571f899caf4949d5d46f49db7.tar.gz notes-21a13652df728c9571f899caf4949d5d46f49db7.zip | |
deploy: 7ca41565c4e70b212cb88a4d18c18fa35768df6d
Diffstat (limited to 'tools/awk.html')
| -rw-r--r-- | tools/awk.html | 403 |
1 files changed, 0 insertions, 403 deletions
diff --git a/tools/awk.html b/tools/awk.html deleted file mode 100644 index bdf80b2..0000000 --- a/tools/awk.html +++ /dev/null @@ -1,403 +0,0 @@ -<!DOCTYPE HTML> -<html lang="en" class="light" dir="ltr"> - <head> - <!-- Book generated using mdBook --> - <meta charset="UTF-8"> - <title>awk - 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 ? "navy" : "light"; - </script> - - <!-- Work around some values being stored in localStorage wrapped in quotes --> - <script> - try { - var theme = localStorage.getItem('mdbook-theme'); - var sidebar = localStorage.getItem('mdbook-sidebar'); - - if (theme.startsWith('"') && theme.endsWith('"')) { - localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1)); - } - - if (sidebar.startsWith('"') && sidebar.endsWith('"')) { - localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1)); - } - } catch (e) { } - </script> - - <!-- Set the theme before any content is loaded, prevents flash --> - <script> - var theme; - try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { } - if (theme === null || theme === undefined) { theme = default_theme; } - var html = document.querySelector('html'); - html.classList.remove('light') - html.classList.add(theme); - var body = document.querySelector('body'); - body.classList.remove('no-js') - body.classList.add('js'); - </script> - - <input type="checkbox" id="sidebar-toggle-anchor" 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">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" class="active"><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> - </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" id="navy">Navy</button></li> - <li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li> - </ul> - <button id="search-toggle" class="icon-button" type="button" title="Search. (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="awk1"><a class="header" href="#awk1">awk(1)</a></h1> -<pre><code class="language-markdown">awk [opt] program [input] - -F <sepstr> field separator string (can be regex) - program awk program - input file or stdin if not file given -</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 } -</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 ----> ∀ pattern matched - | | - v v -fields ----> run associated action -</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 & 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 }' <file> -</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 }' <file> -</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 }' -</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") && !($1 ~ "BAR")) { print } }' -</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) }' -</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 }' -</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/<pid>/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> - - </main> - - <nav class="nav-wrapper" aria-label="Page navigation"> - <!-- Mobile navigation buttons --> - <a rel="prev" href="../tools/git.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left"> - <i class="fa fa-angle-left"></i> - </a> - - <a rel="next prefetch" href="../tools/emacs.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="prev" href="../tools/git.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left"> - <i class="fa fa-angle-left"></i> - </a> - - <a rel="next prefetch" href="../tools/emacs.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> |