wiki.bash-hackers.org/commands/builtin/mapfile

475 lines
34 KiB
Plaintext
Raw Normal View History

2023-04-14 13:44:41 +02:00
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" dir="ltr" class="no-js">
<head><script type="text/javascript" src="/_static/js/bundle-playback.js?v=TPXmWR5s" charset="utf-8"></script>
<script type="text/javascript" src="/_static/js/wombat.js?v=txqj7nKC" charset="utf-8"></script>
<script type="text/javascript">
__wm.init("http://web.archive.org/web");
__wm.wombat("https://wiki.bash-hackers.org/commands/builtin/mapfile?do=edit","20221205021326","http://web.archive.org/","web","/_static/",
"1670206406");
</script>
<link rel="stylesheet" type="text/css" href="/_static/css/banner-styles.css?v=S1zqJCYt" />
<link rel="stylesheet" type="text/css" href="/_static/css/iconochive.css?v=qtvMKcIJ" />
<!-- End Wayback Rewrite JS Include -->
<meta charset="UTF-8"/>
<title>The mapfile builtin command [Bash Hackers Wiki]</title>
<script>(function(H){H.className=H.className.replace(/\bno-js\b/,'js')})(document.documentElement)</script>
<meta name="viewport" content="width=device-width,initial-scale=1"/>
<link rel="shortcut icon" href="/web/20221205021326im_/https://wiki.bash-hackers.org/lib/tpl/bootstrap3/images/favicon.ico"/>
<link rel="apple-touch-icon" href="/web/20221205021326im_/https://wiki.bash-hackers.org/lib/tpl/bootstrap3/images/apple-touch-icon.png"/>
<meta name="generator" content="DokuWiki"/>
<meta name="robots" content="noindex,nofollow"/>
<link type="text/css" rel="stylesheet" href="/web/20221205021326cs_/https://wiki.bash-hackers.org/lib/tpl/bootstrap3/assets/bootstrap/default/bootstrap.min.css"/>
<link rel="search" type="application/opensearchdescription+xml" href="/web/20221205021326/https://wiki.bash-hackers.org/lib/exe/opensearch.php" title="Bash Hackers Wiki"/>
<link rel="start" href="/"/>
<link rel="contents" href="/commands/builtin/mapfile?do=index" title="Sitemap"/>
<link rel="manifest" href="/web/20221205021326/https://wiki.bash-hackers.org/lib/exe/manifest.php"/>
<link rel="alternate" type="application/rss+xml" title="Recent Changes" href="/web/20221205021326/https://wiki.bash-hackers.org/feed.php"/>
<link rel="alternate" type="application/rss+xml" title="Current namespace" href="/web/20221205021326/https://wiki.bash-hackers.org/feed.php?mode=list&amp;ns=commands:builtin"/>
<link rel="alternate" type="text/html" title="Plain HTML" href="/web/20221205021326/https://wiki.bash-hackers.org/_export/xhtml/commands/builtin/mapfile"/>
<link rel="alternate" type="text/plain" title="Wiki Markup" href="/web/20221205021326/https://wiki.bash-hackers.org/_export/raw/commands/builtin/mapfile"/>
<link rel="stylesheet" type="text/css" href="/web/20221205021326cs_/https://wiki.bash-hackers.org/lib/exe/css.php?t=bootstrap3&amp;tseed=54923c3deda180f2db5bd755cd8fbf1a"/>
<!--[if gte IE 9]><!-->
<script type="text/javascript">/*<![CDATA[*/var NS='commands:builtin';var JSINFO = {"updatable":1,"userreplace":1,"default_macro_string":"","plugins":{"edittable":{"default columnwidth":""}},"move_renameokay":false,"isadmin":0,"isauth":0,"bootstrap3":{"mode":"source","toc":[],"config":{"collapsibleSections":0,"fixedTopNavbar":1,"showSemanticPopup":0,"sidebarOnNavbar":0,"tagsOnTop":1,"tocAffix":1,"tocCollapseOnScroll":1,"tocCollapsed":0,"tocLayout":"default","useAnchorJS":1,"useAlternativeToolbarIcons":1}},"id":"commands:builtin:mapfile","namespace":"commands:builtin","ACT":"source","useHeadingNavigation":1,"useHeadingContent":1};
/*!]]>*/</script>
<script type="text/javascript" charset="utf-8" src="/web/20221205021326js_/https://wiki.bash-hackers.org/lib/exe/jquery.php?tseed=23f888679b4f1dc26eef34902aca964f"></script>
<script type="text/javascript" charset="utf-8" src="/web/20221205021326js_/https://wiki.bash-hackers.org/lib/exe/js.php?t=bootstrap3&amp;tseed=54923c3deda180f2db5bd755cd8fbf1a"></script>
<script type="text/javascript">/*<![CDATA[*/if (typeof IconifyConfig == 'undefined') { var IconifyConfig = { 'defaultAPI' : '/lib/tpl/bootstrap3/iconify.php?prefix={prefix}&icons={icons}' } }
/*!]]>*/</script>
<script type="text/javascript" src="/web/20221205021326js_/https://wiki.bash-hackers.org/lib/tpl/bootstrap3/assets/bootstrap/js/bootstrap.min.js"></script>
<script type="text/javascript" src="/web/20221205021326js_/https://wiki.bash-hackers.org/lib/tpl/bootstrap3/assets/anchorjs/anchor.min.js"></script>
<script type="text/javascript" src="/web/20221205021326js_/https://wiki.bash-hackers.org/lib/tpl/bootstrap3/assets/typeahead/bootstrap3-typeahead.min.js"></script>
<script type="text/javascript" src="/web/20221205021326js_/https://wiki.bash-hackers.org/lib/tpl/bootstrap3/assets/iconify/iconify.min.js"></script>
<script type="text/javascript" src="/web/20221205021326js_/https://wiki.bash-hackers.org/lib/tpl/bootstrap3/assets/iconify/plugins/fa.js"></script>
<!--<![endif]-->
<style type="text/css">@media screen { body { margin-top: 65px; } #dw__toc.affix { top: 55px; position: fixed !important; } #dw__toc .nav .nav .nav { display: none; } }</style>
<!--[if lt IE 9]>
<script type="text/javascript" src="https://oss.maxcdn.com/html5shiv/3.7.2/html5shiv.min.js"></script>
<script type="text/javascript" src="https://oss.maxcdn.com/respond/1.4.2/respond.min.js"></script>
<![endif]-->
</head>
<body class="default dokuwiki mode_source tpl_bootstrap3 dw-page-on-panel dw-fluid-container" data-page-id="commands:builtin:mapfile"><div class="dokuwiki">
<header id="dokuwiki__header" class="dw-container dokuwiki container-fluid mx-5">
<!-- navbar -->
<nav id="dw__navbar" class="navbar navbar-fixed-top navbar-default" role="navigation">
<div class="dw-container container-fluid mx-5">
<div class="navbar-header">
<button class="navbar-toggle" type="button" data-toggle="collapse" data-target=".navbar-collapse">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand d-flex align-items-center" href="/web/20221205021326/https://wiki.bash-hackers.org/start" accesskey="h" title="Bash Hackers Wiki"><img id="dw__logo" class="pull-left h-100 mr-4" alt="Bash Hackers Wiki" src="/web/20221205021326im_/https://wiki.bash-hackers.org/lib/tpl/bootstrap3/images/logo.png"/><div class="pull-right"><div id="dw__title">Bash Hackers Wiki</div></div></a>
</div>
<div class="collapse navbar-collapse">
<div class="navbar-right" id="dw__navbar_items">
<!-- navbar-searchform -->
<form action="/web/20221205021326/https://wiki.bash-hackers.org/commands/builtin/mapfile" accept-charset="utf-8" class="navbar-form navbar-left search" id="dw__search" method="get" role="search">
<div class="input-group">
<input id="qsearch" autocomplete="off" type="search" placeholder="Search" value="" accesskey="f" name="q" class="form-control" title="[F]"/>
<div class="input-group-btn">
<button class="btn btn-default" type="submit" title="Search">
<span class="iconify" data-icon="mdi:magnify"></span> </button>
</div>
</div>
<input type="hidden" name="do" value="search"/>
</form>
<!-- /navbar-searchform -->
<!-- tools-menu -->
<ul class="nav navbar-nav dw-action-icon" id="dw__tools">
<li class="dropdown">
<a href="" class="dropdown-toggle" data-target="#" data-toggle="dropdown" title="" role="button" aria-haspopup="true" aria-expanded="false">
<span class="iconify" data-icon="mdi:wrench"></span> <span class="hidden-lg hidden-md hidden-sm">Tools</span> <span class="caret"></span>
</a>
<ul class="dropdown-menu tools" role="menu">
<li class="dropdown-header">
<span class="iconify" data-icon="mdi:account"></span> User Tools </li>
<li class="action"><a href="/web/20221205021326/https://wiki.bash-hackers.org/commands/builtin/mapfile?do=register" title="Register" rel="nofollow" class="menuitem register"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewbox="0 0 24 24"><path d="M15 14c-2.67 0-8 1.33-8 4v2h16v-2c0-2.67-5.33-4-8-4m-9-4V7H4v3H1v2h3v3h2v-3h3v-2m6 2a4 4 0 0 0 4-4 4 4 0 0 0-4-4 4 4 0 0 0-4 4 4 4 0 0 0 4 4z"/></svg><span>Register</span></a></li><li class="action"><a href="/web/20221205021326/https://wiki.bash-hackers.org/commands/builtin/mapfile?do=login&amp;sectok=" title="Log In" rel="nofollow" class="menuitem login"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewbox="0 0 24 24"><path d="M10 17.25V14H3v-4h7V6.75L15.25 12 10 17.25M8 2h9a2 2 0 0 1 2 2v16a2 2 0 0 1-2 2H8a2 2 0 0 1-2-2v-4h2v4h9V4H8v4H6V4a2 2 0 0 1 2-2z"/></svg><span>Log In</span></a></li>
<li class="divider" role="separator"></li>
<li class="dropdown-header">
<span class="iconify" data-icon="mdi:toolbox"></span> Site Tools </li>
<li class="action"><a href="/web/20221205021326/https://wiki.bash-hackers.org/commands/builtin/mapfile?do=recent" title="Recent Changes [r]" rel="nofollow" accesskey="r" class="menuitem recent"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewbox="0 0 24 24"><path d="M15 13h1.5v2.82l2.44 1.41-.75 1.3L15 16.69V13m4-5H5v11h4.67c-.43-.91-.67-1.93-.67-3a7 7 0 0 1 7-7c1.07 0 2.09.24 3 .67V8M5 21a2 2 0 0 1-2-2V5c0-1.11.89-2 2-2h1V1h2v2h8V1h2v2h1a2 2 0 0 1 2 2v6.1c1.24 1.26 2 2.99 2 4.9a7 7 0 0 1-7 7c-1.91 0-3.64-.76-4.9-2H5m11-9.85A4.85 4.85 0 0 0 11.15 16c0 2.68 2.17 4.85 4.85 4.85A4.85 4.85 0 0 0 20.85 16c0-2.68-2.17-4.85-4.85-4.85z"/></svg><span>Recent Changes</span></a></li><li class="action"><a href="/web/20221205021326/https://wiki.bash-hackers.org/commands/builtin/mapfile?do=media&amp;ns=commands%3Abuiltin" title="Media Manager" rel="nofollow" class="menuitem media"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewbox="0 0 24 24"><path d="M7 15l4.5-6 3.5 4.5 2.5-3L21 15m1-11h-8l-2-2H6a2 2 0 0 0-2 2v12a2 2 0 0 0 2 2h16a2 2 0 0 0 2-2V6a2 2 0 0 0-2-2M2 6H0v14a2 2 0 0 0 2 2h18v-2H2V6z"/></svg><span>Media Manager</span></a></li><li class="action"><a href="/web/20221205021326/https://wiki.bash-hackers.org/commands/builtin/mapfile?do=index" title="Sitemap [x]" rel="nofollow" accesskey="x" class="menuitem index"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewbox="0 0 24 24"><path d="M3 3h6v4H3V3m12 7h6v4h-6v-4m0 7h6v4h-6v-4m-2-4H7v5h6v2H5V9h2v2h6v2z"/></svg><span>Sitemap</span></a></li>
<li class="divider" role="separator"></li>
<li class="dropdown-header">
<span class="iconify" data-icon="mdi:file-document-outline"></span> Page Tools </li>
<li class="action"><a href="/web/20221205021326/https://wiki.bash-hackers.org/commands/builtin/mapfile?do=" title="Show page [v]" rel="nofollow" accesskey="v" class="menuitem show"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewbox="0 0 24 24"><path d="M13 9h5.5L13 3.5V9M6 2h8l6 6v12a2 2 0 0 1-2 2H6a2 2 0 0 1-2-2V4c0-1.11.89-2 2-2m9 16v-2H6v2h9m3-4v-2H6v2h12z"/></svg><span>Show page</span></a></li><li class="action"><a href="/web/20221205021326/https://wiki.bash-hackers.org/commands/builtin/mapfile?do=revisions" title="Old revisions [o]" rel="nofollow" accesskey="o" class="menuitem revs"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewbox="0 0 24 24"><path d="M11 7v5.11l4.71 2.79.79-1.28-4-2.37V7m0-5C8.97 2 5.91 3.92 4.27 6.77L2 4.5V11h6.5L5.75 8.25C6.96 5.73 9.5 4 12.5 4a7.5 7.5 0 0 1 7.5 7.5 7.5 7.5 0 0 1-7.5 7.5c-3.27 0-6.03-2.09-7.06-5h-2.1c1.1 4.03 4.77 7 9.16 7 5.24 0 9.5-4.25 9.5-9.5A9.5 9.5 0 0 0 12.5 2z"/></svg><span>Old revisions</span></a></li><li class="action"><a href="/web/20221205021326/https://wiki.bash-hackers.org/commands/builtin/mapfile?do=backlink" title="Backlinks" rel="nofollow" class="menuitem backlink"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewbox="0 0 24 24"><path d="M10.59 13.41c.41.39.41 1.03 0 1.42-.39.39-1.03.39-1.42 0a5.003 5.003 0 0 1 0-7.07l3.54-3.54a5.003 5.003 0 0 1 7.07 0 5.003 5.003 0 0 1 0 7.07l-1.49 1.49c.01-.82-.12-1.64-.4-2.42l.47-.48a2.982 2.982 0 0 0 0-4.24 2.982 2.982 0 0 0-4.24 0l-3.53 3.53a2.982 2.982 0 0 0 0 4.24m2.82-4.24c.39-.39 1.03-.39 1.42 0a5.003 5.003 0 0 1 0 7.07l-3.54 3.54a5.003 5.003 0 0 1-7.07 0 5.003 5.003 0 0 1 0-7.07l1.49-1.49c-.01.82.12 1.64.4 2.43l-.47.47a2.982 2.982 0 0 0 0 4.24 2.982 2.982 0 0 0 4.24 0l3.53-3.53a2.982 2.982 0 0 0 0-4.24.973.973 0 0 1 0-1.42z"/></svg><span>Backlinks</span></a></li><li class="action"><a href="#dokuwiki__top" title="Back to top [t]" rel="nofollow" accesskey="t" class="menuitem top"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8v12z"/></svg><span>Back to top</span></a></li>
</ul>
</li>
</ul>
<!-- /tools-menu -->
<ul class="nav navbar-nav">
<li>
<span class="dw__actions dw-action-icon">
<a href="/web/20221205021326/https://wiki.bash-hackers.org/commands/builtin/mapfile?do=register" title="Register" rel="nofollow" class="menuitem register btn btn-success navbar-btn"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewbox="0 0 24 24"><path d="M15 14c-2.67 0-8 1.33-8 4v2h16v-2c0-2.67-5.33-4-8-4m-9-4V7H4v3H1v2h3v3h2v-3h3v-2m6 2a4 4 0 0 0 4-4 4 4 0 0 0-4-4 4 4 0 0 0-4 4 4 4 0 0 0 4 4z"/></svg><span class=""> Register</span></a><a href="/web/20221205021326/https://wiki.bash-hackers.org/commands/builtin/mapfile?do=login&amp;sectok=" title="Log In" rel="nofollow" class="menuitem login btn btn-default navbar-btn"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewbox="0 0 24 24"><path d="M10 17.25V14H3v-4h7V6.75L15.25 12 10 17.25M8 2h9a2 2 0 0 1 2 2v16a2 2 0 0 1-2 2H8a2 2 0 0 1-2-2v-4h2v4h9V4H8v4H6V4a2 2 0 0 1 2-2z"/></svg><span class=""> Log In</span></a> </span>
</li>
</ul>
</div>
</div>
</div>
</nav>
<!-- navbar -->
<div align="center">
<script async src="//web.archive.org/web/20221205021326js_/https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>
<!-- BHORG_BOTTOM -->
<ins class="adsbygoogle" style="display:inline-block;width:728px;height:90px" data-ad-client="ca-pub-4658830517838678" data-ad-slot="1603598940"></ins>
<script>
(adsbygoogle = window.adsbygoogle || []).push({});
</script>
</div>
</header>
<a name="dokuwiki__top" id="dokuwiki__top"></a>
<main role="main" class="dw-container pb-5 dokuwiki container-fluid mx-5">
<div id="dokuwiki__pageheader">
<!-- breadcrumbs -->
<nav id="dw__breadcrumbs" class="small">
<hr/>
<div class="dw__youarehere">
<ol class="breadcrumb" itemscope itemtype="http://schema.org/BreadcrumbList"><li>You are here</li><li itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem"><a href="/web/20221205021326/https://wiki.bash-hackers.org/start" itemprop="item" title="start"><span itemprop="name"><span class="iconify" data-icon="mdi:home"></span></span></a></li><li itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem"><a itemprop="item" href="/web/20221205021326/https://wiki.bash-hackers.org/commands/start" class="wikilink1" title="commands:start">Commands</a></li><li itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem"><a itemprop="item" href="/web/20221205021326/https://wiki.bash-hackers.org/commands/builtin/start" class="wikilink1" title="commands:builtin:start">Builtin Commands</a></li><li class="active" itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem"><span itemprop="name"><a itemprop="item" href="/web/20221205021326/https://wiki.bash-hackers.org/commands/builtin/mapfile" class="wikilink1" title="commands:builtin:mapfile">The mapfile builtin command</a></span></li></ol> </div>
<div class="dw__breadcrumbs hidden-print">
<ol class="breadcrumb"><li>Trace</li> </div>
<hr/>
</nav>
<!-- /breadcrumbs -->
<p class="text-right">
<span class="pageId ml-1 label label-primary">commands:builtin:mapfile</span> </p>
<div id="dw__msgarea" class="small">
</div>
</div>
<div class="row">
<article id="dokuwiki__content" class="col-sm-12 col-md-12 " itemscope itemtype="http://schema.org/Article" itemref="dw__license">
<!-- page-tools -->
<nav id="dw__pagetools" class="hidden-print">
<div class="tools panel panel-default">
<ul class="nav nav-stacked nav-pills text-muted">
<li class="action"><a href="/web/20221205021326/https://wiki.bash-hackers.org/commands/builtin/mapfile?do=" title="Show page [v]" rel="nofollow" accesskey="v" class="menuitem show"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewbox="0 0 24 24"><path d="M13 9h5.5L13 3.5V9M6 2h8l6 6v12a2 2 0 0 1-2 2H6a2 2 0 0 1-2-2V4c0-1.11.89-2 2-2m9 16v-2H6v2h9m3-4v-2H6v2h12z"/></svg><span>Show page</span></a></li><li class="action"><a href="/web/20221205021326/https://wiki.bash-hackers.org/commands/builtin/mapfile?do=revisions" title="Old revisions [o]" rel="nofollow" accesskey="o" class="menuitem revs"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewbox="0 0 24 24"><path d="M11 7v5.11l4.71 2.79.79-1.28-4-2.37V7m0-5C8.97 2 5.91 3.92 4.27 6.77L2 4.5V11h6.5L5.75 8.25C6.96 5.73 9.5 4 12.5 4a7.5 7.5 0 0 1 7.5 7.5 7.5 7.5 0 0 1-7.5 7.5c-3.27 0-6.03-2.09-7.06-5h-2.1c1.1 4.03 4.77 7 9.16 7 5.24 0 9.5-4.25 9.5-9.5A9.5 9.5 0 0 0 12.5 2z"/></svg><span>Old revisions</span></a></li><li class="action"><a href="/web/20221205021326/https://wiki.bash-hackers.org/commands/builtin/mapfile?do=backlink" title="Backlinks" rel="nofollow" class="menuitem backlink"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewbox="0 0 24 24"><path d="M10.59 13.41c.41.39.41 1.03 0 1.42-.39.39-1.03.39-1.42 0a5.003 5.003 0 0 1 0-7.07l3.54-3.54a5.003 5.003 0 0 1 7.07 0 5.003 5.003 0 0 1 0 7.07l-1.49 1.49c.01-.82-.12-1.64-.4-2.42l.47-.48a2.982 2.982 0 0 0 0-4.24 2.982 2.982 0 0 0-4.24 0l-3.53 3.53a2.982 2.982 0 0 0 0 4.24m2.82-4.24c.39-.39 1.03-.39 1.42 0a5.003 5.003 0 0 1 0 7.07l-3.54 3.54a5.003 5.003 0 0 1-7.07 0 5.003 5.003 0 0 1 0-7.07l1.49-1.49c-.01.82.12 1.64.4 2.43l-.47.47a2.982 2.982 0 0 0 0 4.24 2.982 2.982 0 0 0 4.24 0l3.53-3.53a2.982 2.982 0 0 0 0-4.24.973.973 0 0 1 0-1.42z"/></svg><span>Backlinks</span></a></li><li class="action"><a href="#dokuwiki__top" title="Back to top [t]" rel="nofollow" accesskey="t" class="menuitem top"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8v12z"/></svg><span>Back to top</span></a></li> </ul>
</div>
</nav>
<!-- /page-tools -->
<div class="panel panel-default px-3 py-2" itemprop="articleBody">
<div class="page panel-body">
<div class="dw-content-page "><!-- content --><div class="dw-content"><p>
This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong.
</p>
<div class="editBox" role="application">
<div class="toolbar group">
<div id="draft__status" class="draft__status"></div>
<div id="tool__bar" class="tool__bar"></div>
</div>
<form id="dw__editform" method="post" action="" accept-charset="utf-8" class=" form-inline"><div class="no">
<input type="hidden" name="sectok" value=""/><input type="hidden" name="id" value="commands:builtin:mapfile"/><input type="hidden" name="rev" value="0"/><input type="hidden" name="date" value="0"/><input type="hidden" name="prefix" value="."/><input type="hidden" name="suffix" value=""/><input type="hidden" name="changecheck" value="63f77457543ee931323cfae67120699a"/><input type="hidden" name="target" value="section"/><textarea name="wikitext" id="wiki__text" dir="auto" class="edit form-control" cols="80" rows="10" tabindex="1" readonly="readonly">
====== The mapfile builtin command ======
===== Synopsis =====
&lt;code&gt;
mapfile [-n COUNT] [-O ORIGIN] [-s COUNT] [-t] [-u FD] [-C CALLBACK] [-c QUANTUM] [ARRAY]
&lt;/code&gt;
&lt;code&gt;
readarray [-n COUNT] [-O ORIGIN] [-s COUNT] [-t] [-u FD] [-C CALLBACK] [-c QUANTUM] [ARRAY]
&lt;/code&gt;
===== Description =====
This builtin is also accessible using the command name ''readarray''.
''mapfile'' is one of the two builtin commands primarily intended for handling standard input (the other being ''read''). ''mapfile'' reads lines of standard input and assigns each to the elements of an indexed array. If no array name is given, the default array name is ''MAPFILE''. The target array must be a &quot;normal&quot; integer indexed array.
''mapfile'' returns success (0) unless an invalid option is given or the given array ''ARRAY'' is set readonly.
^Option ^Description ^
|''-c QUANTUM'' |Specifies the number of lines that have to be read between every call to the callback specified with ''-C''. The default QUANTUM is 5000|
|''-C CALLBACK'' |Specifies a callback. The string ''CALLBACK'' can be any shell code, the index of the array that will be assigned, and the line is appended at evaluation time. |
|''-n COUNT'' |Reads at most ''COUNT'' lines, then terminates. If ''COUNT'' is 0, then all lines are read (default). |
|''-O ORIGIN'' |Starts populating the given array ''ARRAY'' at the index ''ORIGIN'' rather than clearing it and starting at index 0. |
|''-s COUNT'' |Discards the first ''COUNT'' lines read. |
|''-t'' |Remove any trailing newline from a line read, before it is assigned to an array element. |
|''-u FD'' |Read from filedescriptor ''FD'' rather than standard input. |
While ''mapfile'' isn't a common or portable shell feature, it's functionality will be familiar to many programmers. Almost all programming languages (aside from shells) with support for compound datatypes like arrays, and which handle open file objects in the traditional way, have some analogous shortcut for easily reading all lines of some input as a standard feature. In Bash, ''mapfile'' in itself can't do anything that couldn't already be done using read and a loop, and if portability is even a slight concern, should never be used. However, it does //significantly// outperform a read loop, and can make for shorter and cleaner code - especially convenient for interactive use.
===== Examples =====
Here's a real-world example of interactive use borrowed from Gentoo workflow. Xorg updates require rebuilding drivers, and the Gentoo-suggested command is less than ideal, so let's Bashify it. The first command produces a list of packages, one per line. We can read those into the array named &quot;args&quot; using ''mapfile'', stripping trailing newlines with the '-t' option. The resulting array is then expanded into the arguments of the &quot;emerge&quot; command - an interface to Gentoo's package manager. This type of usage can make for a safe and effective replacement for xargs(1) in certain situations. Unlike xargs, all arguments are guaranteed to be passed to a single invocation of the command with no wordsplitting, pathname expansion, or other monkey business.
&lt;code&gt;# eix --only-names -IC x11-drivers | { mapfile -t args; emerge -av1 &quot;${args[@]}&quot; &lt;&amp;1; }&lt;/code&gt;
Note the use of command grouping to keep the emerge command inside the pipe's subshell and within the scope of &quot;args&quot;. Also note the unusual redirection. This is because the -a flag makes emerge interactive, asking the user for confirmation before continuing, and checking with isatty(3) to abort if stdin isn't pointed at a terminal. Since stdin of the entire command group is still coming from the pipe even though mapfile has read all available input, we just borrow FD 1 as it just so happens to be pointing where we want it. More on this over at greycat's wiki: http://mywiki.wooledge.org/BashFAQ/024
==== The callback ===
This is one of the more unusual features of a Bash builtin. As far as I'm able to tell, the exact behavior is as follows: If defined, as each line is read, the code contained within the string argument to the -C flag is evaluated and executed //before// the assignment of each array element. There are no restrictions to this string, which can be any arbitrary code, however, two additional &quot;words&quot; are automatically appended to the end before evaluation: the index, and corresponding line of data to be assigned to the next array element. Since all this happens before assignment, the callback feature cannot be used to modify the element to be assigned, though it can read and modify any array elements already assigned.
A very simple example might be to use it as a kind of progress bar. This will print a dot for each line read. Note the escaped comment to hide the appended words from printf.
&lt;code&gt;$ printf '%s\n' {1..5} | mapfile -c 1 -C 'printf . \#' )
.....&lt;/code&gt;
Really, the intended usage is for the callback to just contain the name of a function, with the extra words passed to it as arguments. If you're going to use callbacks at all, this is probably the best way because it allows for easy access to the arguments with no ugly &quot;code in a string&quot;.
&lt;code&gt;
$ foo() { echo &quot;|$1|&quot;; }; mapfile -n 11 -c 2 -C 'foo' &lt;file
|2|
|4|
etc..
&lt;/code&gt;
For the sake of completeness, here are some more complicated examples inspired by a question asked in #bash - how to prepend something to every line of some input, and then output even and odd lines to separate files. This is far from the best possible answer, but hopefully illustrates the callback behavior:
&lt;code&gt;$ { printf 'input%s\n' {1..10} | mapfile -c 1 -C '&gt;&amp;$(( (${#x[@]} % 2) + 3 )) printf -- &quot;%.sprefix %s&quot;' x; } 3&gt;outfile0 4&gt;outfile1
$ cat outfile{0,1}
prefix input1
prefix input3
prefix input5
prefix input7
prefix input9
prefix input2
prefix input4
prefix input6
prefix input8
prefix input10
&lt;/code&gt;
Since redirects are syntactically allowed anywhere in a command, we put it before the printf to stay out of the way of additional arguments. Rather than opening &quot;outfile&lt;n&gt;&quot; for appending on each call by calculating the filename, open an FD for each first and calculate which FD to send output to by measuring the size of x mod 2. The zero-width format specification is used to absorb the index number argument.
Another variation might be to add each of these lines to the elements of separate arrays. I'll leave dissecting this one as an exercise for the reader. This is quite the hack but illustrates some interesting properties of printf -v and mapfile -C (which you should probably never use in real code).
&lt;code&gt;$ y=( 'odd[j]' 'even[j++]' ); printf 'input%s\n' {1..10} | { mapfile -tc 1 -C 'printf -v &quot;${y[${#x[@]} % 2]}&quot; -- &quot;%.sprefix %s&quot;' x; printf '%s\n' &quot;${odd[@]}&quot; '' &quot;${even[@]}&quot;; }
prefix input1
prefix input3
prefix input5
prefix input7
prefix input9
prefix input2
prefix input4
prefix input6
prefix input8
prefix input10
&lt;/code&gt;
This example based on yet another #bash question illustrates mapfile in combination with read. The sample input is the heredoc to ''main''. The goal is to build a &quot;struct&quot; based upon records in the input file made up of the numbers following the colon on each line. Every 3rd line is a key followed by 2 corresponding fields. The showRecord function takes a key and returns the record.
&lt;code&gt;
#!/usr/bin/env bash
showRecord() {
printf 'key[%d] = %d, %d\n' &quot;$1&quot; &quot;${vals[@]:keys[$1]*2:2}&quot;
}
parseRecords() {
trap 'unset -f _f' RETURN
_f() {
local x
IFS=: read -r _ x
((keys[x]=n++))
}
local n
_f
mapfile -tc2 -C _f &quot;$1&quot;
eval &quot;$1&quot;'=(&quot;${'&quot;$1&quot;'[@]##*:}&quot;)' # Return the array with some modification
}
main() {
local -a keys vals
parseRecords vals
showRecord &quot;$1&quot;
}
main &quot;$1&quot; &lt;&lt;-&quot;EOF&quot;
fabric.domain:123
routex:1
routey:2
fabric.domain:321
routex:6
routey:4
EOF
&lt;/code&gt;
For example, running ''scriptname 321'' would output ''key[321] = 6, 4''. Every 2 lines read by ''mapfile'', the function ''_f'' is called, which reads one additional line. Since the first line in the file is a key, and ''_f'' is responsible for the keys, it gets called first so that ''mapfile'' starts by reading the second line of input, calling ''_f'' with each subsequent 2 iterations. The RETURN trap is unimportant.
===== Bugs =====
* Early implementations were buggy. For example, ''mapfile'' filling the readline history buffer with calls to the ''CALLBACK''. This was fixed in 4.1 beta.
* ''mapfile -n'' reads an extra line beyond the last line assigned to the array, through Bash. [[ftp://ftp.gnu.org/gnu/bash/bash-4.2-patches/bash42-035 | Fixed in 4.2.35]].
* ''mapfile'' callbacks could cause a crash if the variable being assigned is manipulated in certain ways. [[https://lists.gnu.org/archive/html/bug-bash/2013-01/msg00039.html]]. Fixed in 4.3.
===== To Do =====
* Create an implementation as a shell function that's portable between Ksh, Zsh, and Bash (and possibly other bourne-like shells with array support).
===== See also =====
* [[syntax:arrays]]
* [[commands:builtin:read]] - If you don't know about this yet, why are you reading this page?
* [[http://mywiki.wooledge.org/BashFAQ/001]] - It's FAQ 1 for a reason.
</textarea>
<div id="wiki__editbar" class="editBar">
<div id="size__ctl">
</div>
</div>
</div></form>
</div>
</div><!-- /content --></div>
</div>
</div>
<div class="small text-right">
<span class="docInfo">
<ul class="list-inline"><li><span class="iconify text-muted" data-icon="mdi:file-document-outline"></span> <span title="commands/builtin/mapfile.txt">commands/builtin/mapfile.txt</span></li><li><span class="iconify text-muted" data-icon="mdi:calendar"></span> Last modified: <span title="2013/08/19 08:09">2013/08/19 08:09</span></li><li class="text-muted">by <bdi>ormaaj</bdi></li></ul> </span>
</div>
</article>
</div>
</main>
<footer id="dw__footer" class="dw-container py-5 dokuwiki container-fluid">
<hr/>
<div align="center">
<h3><a target="_blank" href="http://web.archive.org/web/20221205021326/http://www.performing-databases.com/">This site is supported by Performing Databases - your experts for database administration</a></h3>
</div>
<hr/>
<div align="center">
<script async src="//web.archive.org/web/20221205021326js_/https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>
<!-- BHORG_BOTTOM -->
<ins class="adsbygoogle" style="display:inline-block;width:728px;height:90px" data-ad-client="ca-pub-4658830517838678" data-ad-slot="1603598940"></ins>
<script>
(adsbygoogle = window.adsbygoogle || []).push({});
</script>
</div>
<!-- footer -->
<div class="dw-container small container-fluid mx-5">
<div class="footer-dw-title">
<div class="media">
<div class="media-left">
<img src="/web/20221205021326im_/https://wiki.bash-hackers.org/lib/tpl/bootstrap3/images/logo.png" alt="Bash Hackers Wiki" class="media-object" style="height:32px"/>
</div>
<div class="media-body">
<div class="row">
<div class="col-sm-2">
<h4 class="media-heading">Bash Hackers Wiki</h4>
<p>
</p>
</div>
<div class="col-sm-10">
</div>
</div>
</div>
</div>
</div>
<div class="footer-license row">
<hr/>
<div id="dw__license" class="col-sm-6">
<p>
<a href="http://web.archive.org/web/20221205021326/http://www.gnu.org/licenses/fdl-1.3.html" title="GNU Free Documentation License 1.3" target="" itemscope itemtype="http://schema.org/CreativeWork" itemprop="license" rel="license" class="license"><img src="/web/20221205021326im_/https://wiki.bash-hackers.org/lib/tpl/bootstrap3/images/license/gnufdl.png" width="24" height="24" alt="gnufdl"/> </a> </p>
<p class="small">
Except where otherwise noted, content on this wiki is licensed under the following license:<br/><a href="http://web.archive.org/web/20221205021326/http://www.gnu.org/licenses/fdl-1.3.html" title="GNU Free Documentation License 1.3" target="" itemscope itemtype="http://schema.org/CreativeWork" itemprop="license" rel="license" class="license">GNU Free Documentation License 1.3</a> </p>
</div>
<div class="col-sm-6">
</div>
</div>
</div>
<!-- /footer -->
</footer>
<a href="#dokuwiki__top" class="back-to-top hidden-print btn btn-default" title="skip to content" accesskey="t">
<span class="iconify" data-icon="mdi:chevron-up"></span> </a>
<div id="screen__mode"> <span class="visible-xs-block"></span>
<span class="visible-sm-block"></span>
<span class="visible-md-block"></span>
<span class="visible-lg-block"></span>
</div>
<img src="/web/20221205021326im_/https://wiki.bash-hackers.org/lib/exe/indexer.php?id=commands%3Abuiltin%3Amapfile&amp;1670206434" width="2" height="1" alt=""/>
</div>
</body>
</html>
<!--
FILE ARCHIVED ON 02:13:26 Dec 05, 2022 AND RETRIEVED FROM THE
INTERNET ARCHIVE ON 11:37:04 Apr 14, 2023.
JAVASCRIPT APPENDED BY WAYBACK MACHINE, COPYRIGHT INTERNET ARCHIVE.
ALL OTHER CONTENT MAY ALSO BE PROTECTED BY COPYRIGHT (17 U.S.C.
SECTION 108(a)(3)).
-->
<!--
playback timings (ms):
captures_list: 109.44
exclusion.robots: 0.196
exclusion.robots.policy: 0.184
RedisCDXSource: 6.529
esindex: 0.009
LoadShardBlock: 76.311 (3)
PetaboxLoader3.datanode: 82.561 (4)
load_resource: 103.442
PetaboxLoader3.resolve: 73.562
-->