mirror of
https://github.com/rawiriblundell/wiki.bash-hackers.org
synced 2024-11-02 00:53:07 +01:00
739 lines
36 KiB
Plaintext
739 lines
36 KiB
Plaintext
<!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/scripting/posparams?do=edit","20220925044221","http://web.archive.org/","web","/_static/",
|
|
"1664080941");
|
|
</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>Handling positional parameters [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/20220925044221im_/https://wiki.bash-hackers.org/lib/tpl/bootstrap3/images/favicon.ico"/>
|
|
<link rel="apple-touch-icon" href="/web/20220925044221im_/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/20220925044221cs_/https://wiki.bash-hackers.org/lib/tpl/bootstrap3/assets/bootstrap/default/bootstrap.min.css"/>
|
|
<link rel="search" type="application/opensearchdescription+xml" href="/web/20220925044221/https://wiki.bash-hackers.org/lib/exe/opensearch.php" title="Bash Hackers Wiki"/>
|
|
<link rel="start" href="/"/>
|
|
<link rel="contents" href="/scripting/posparams?do=index" title="Sitemap"/>
|
|
<link rel="manifest" href="/web/20220925044221/https://wiki.bash-hackers.org/lib/exe/manifest.php"/>
|
|
<link rel="alternate" type="application/rss+xml" title="Recent Changes" href="/web/20220925044221/https://wiki.bash-hackers.org/feed.php"/>
|
|
<link rel="alternate" type="application/rss+xml" title="Current namespace" href="/web/20220925044221/https://wiki.bash-hackers.org/feed.php?mode=list&ns=scripting"/>
|
|
<link rel="alternate" type="text/html" title="Plain HTML" href="/web/20220925044221/https://wiki.bash-hackers.org/_export/xhtml/scripting/posparams"/>
|
|
<link rel="alternate" type="text/plain" title="Wiki Markup" href="/web/20220925044221/https://wiki.bash-hackers.org/_export/raw/scripting/posparams"/>
|
|
<link rel="stylesheet" type="text/css" href="/web/20220925044221cs_/https://wiki.bash-hackers.org/lib/exe/css.php?t=bootstrap3&tseed=54923c3deda180f2db5bd755cd8fbf1a"/>
|
|
<!--[if gte IE 9]><!-->
|
|
<script type="text/javascript">/*<![CDATA[*/var NS='scripting';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":"scripting:posparams","namespace":"scripting","ACT":"source","useHeadingNavigation":1,"useHeadingContent":1};
|
|
/*!]]>*/</script>
|
|
<script type="text/javascript" charset="utf-8" src="/web/20220925044221js_/https://wiki.bash-hackers.org/lib/exe/jquery.php?tseed=23f888679b4f1dc26eef34902aca964f"></script>
|
|
<script type="text/javascript" charset="utf-8" src="/web/20220925044221js_/https://wiki.bash-hackers.org/lib/exe/js.php?t=bootstrap3&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/20220925044221js_/https://wiki.bash-hackers.org/lib/tpl/bootstrap3/assets/bootstrap/js/bootstrap.min.js"></script>
|
|
<script type="text/javascript" src="/web/20220925044221js_/https://wiki.bash-hackers.org/lib/tpl/bootstrap3/assets/anchorjs/anchor.min.js"></script>
|
|
<script type="text/javascript" src="/web/20220925044221js_/https://wiki.bash-hackers.org/lib/tpl/bootstrap3/assets/typeahead/bootstrap3-typeahead.min.js"></script>
|
|
<script type="text/javascript" src="/web/20220925044221js_/https://wiki.bash-hackers.org/lib/tpl/bootstrap3/assets/iconify/iconify.min.js"></script>
|
|
<script type="text/javascript" src="/web/20220925044221js_/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="scripting:posparams"><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/20220925044221/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/20220925044221im_/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/20220925044221/https://wiki.bash-hackers.org/scripting/posparams" 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/20220925044221/https://wiki.bash-hackers.org/scripting/posparams?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/20220925044221/https://wiki.bash-hackers.org/scripting/posparams?do=login&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/20220925044221/https://wiki.bash-hackers.org/scripting/posparams?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/20220925044221/https://wiki.bash-hackers.org/scripting/posparams?do=media&ns=scripting" 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/20220925044221/https://wiki.bash-hackers.org/scripting/posparams?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/20220925044221/https://wiki.bash-hackers.org/scripting/posparams?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/20220925044221/https://wiki.bash-hackers.org/scripting/posparams?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/20220925044221/https://wiki.bash-hackers.org/scripting/posparams?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/20220925044221/https://wiki.bash-hackers.org/scripting/posparams?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/20220925044221/https://wiki.bash-hackers.org/scripting/posparams?do=login&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/20220925044221js_/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/20220925044221/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/20220925044221/https://wiki.bash-hackers.org/scripting/start" class="wikilink2" title="scripting:start" rel="nofollow">scripting</a></li><li class="active" itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem"><span itemprop="name"><a itemprop="item" href="/web/20220925044221/https://wiki.bash-hackers.org/scripting/posparams" class="wikilink1" title="scripting:posparams">Handling positional parameters</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">scripting:posparams</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/20220925044221/https://wiki.bash-hackers.org/scripting/posparams?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/20220925044221/https://wiki.bash-hackers.org/scripting/posparams?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/20220925044221/https://wiki.bash-hackers.org/scripting/posparams?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="scripting:posparams"/><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="dd33df2b85e12723c1c6de6098c93b57"/><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">
|
|
====== Handling positional parameters ======
|
|
|
|
{{keywords>bash shell scripting arguments positional parameters options}}
|
|
|
|
|
|
===== Intro =====
|
|
|
|
The day will come when you want to give arguments to your scripts. These arguments are known as **positional parameters**. Some relevant special parameters are described below:
|
|
^Parameter(s)^Description^
|
|
|''$0''|the first positional parameter, equivalent to ''argv[0]'' in C, see [[scripting:posparams#the_first_argument | the first argument]]|
|
|
|''$FUNCNAME''| the function name (__**attention**__: inside a function, ''$0'' is still the ''$0'' of the shell, **not** the function name)|
|
|
|''$1 ... $9''|the argument list elements from 1 to 9|
|
|
|''${10} ... ${N}''|the argument list elements beyond 9 (note the [[syntax:pe | parameter expansion]] syntax!)|
|
|
|''$*''|all positional parameters except ''$0'', see [[scripting:posparams#mass_usage | mass usage]]|
|
|
|''$@''|all positional parameters except ''$0'', see [[scripting:posparams#mass_usage | mass usage]]|
|
|
|''$#''|the number of arguments, not counting ''$0''|
|
|
|
|
|
|
These positional parameters reflect exactly what was given to the
|
|
script when it was called.
|
|
|
|
Option-switch parsing (e.g. ''-h'' for displaying help) is not performed at
|
|
this point.
|
|
|
|
See also [[dict:terms:parameter | the dictionary entry for "parameter"]].
|
|
|
|
|
|
===== The first argument =====
|
|
|
|
The very first argument you can access is referenced as ''$0''. It
|
|
is usually set to the script's name exactly as called, and it's
|
|
set on shell initialization:
|
|
|
|
__Testscript__ - it just echos ''$0'':
|
|
<code>
|
|
#!/bin/bash
|
|
echo "$0"
|
|
</code>
|
|
You see, ''$0'' is always set to the name the script is called with (''>'' is the prompt...):
|
|
<code>
|
|
> ./testscript
|
|
./testscript
|
|
</code>
|
|
<code>
|
|
> /usr/bin/testscript
|
|
/usr/bin/testscript
|
|
</code>
|
|
|
|
However, this isn't true for login shells:
|
|
<code>
|
|
> echo "$0"
|
|
-bash
|
|
</code>
|
|
|
|
In other terms, ''$0'' is not a positional parameter, it's a
|
|
special parameter independent from the positional parameter list. It
|
|
can be set to anything. In the **ideal** case it's the pathname
|
|
of the script, but since this gets set on invocation, the invoking
|
|
program can easily influence it (the ''login'' program does that for
|
|
login shells, by prefixing a dash, for example).
|
|
|
|
Inside a function, ''$0'' still behaves as described above. To
|
|
get the function name, use ''$FUNCNAME''.
|
|
|
|
===== Shifting =====
|
|
|
|
The builtin command ''shift'' is used to change the positional parameter values:
|
|
* ''$1'' will be discarded
|
|
* ''$2'' will become ''$1''
|
|
* ''$3'' will become ''$2''
|
|
* ...
|
|
* in general: ''$N'' will become ''$N-1''
|
|
|
|
The command can take a number as argument: Number of positions to shift.
|
|
e.g. ''shift 4'' shifts ''$5'' to ''$1''.
|
|
|
|
===== Using them =====
|
|
|
|
Enough theory, you want to access your script-arguments. Well, here we go.
|
|
|
|
==== One by one ====
|
|
|
|
One way is to access specific parameters:
|
|
<code>
|
|
#!/bin/bash
|
|
echo "Total number of arguments: $#"
|
|
echo "Argument 1: $1"
|
|
echo "Argument 2: $2"
|
|
echo "Argument 3: $3"
|
|
echo "Argument 4: $4"
|
|
echo "Argument 5: $5"
|
|
</code>
|
|
|
|
While useful in another situation, this way is lacks flexibility.
|
|
The maximum number of arguments is a fixedvalue
|
|
- which is a bad idea if you write a script that takes many filenames
|
|
as arguments.
|
|
|
|
=> forget that one
|
|
|
|
==== Loops ====
|
|
|
|
There are several ways to loop through the positional parameters.
|
|
|
|
----
|
|
|
|
You can code a [[syntax:ccmd:c_for | C-style for-loop]] using ''$#''
|
|
as the end value. On every iteration, the ''shift''-command is used to
|
|
shift the argument list:
|
|
|
|
<code>
|
|
numargs=$#
|
|
for ((i=1 ; i <= numargs ; i++))
|
|
do
|
|
echo "$1"
|
|
shift
|
|
done
|
|
</code>
|
|
|
|
Not very stylish, but usable. The ''numargs'' variable is used
|
|
to store the initial value of ''$#'' because the shift command
|
|
will change it as the script runs.
|
|
|
|
----
|
|
|
|
Another way to iterate one argument at a time is the ''for'' loop
|
|
without a given wordlist. The loop uses the positional parameters as a wordlist:
|
|
|
|
<code>
|
|
for arg
|
|
do
|
|
echo "$arg"
|
|
done
|
|
</code>
|
|
__Advantage:__ The positional parameters will be preserved
|
|
|
|
----
|
|
|
|
The next method is similar to the first example (the ''for'' loop), but
|
|
it doesn't test for reaching ''$#''. It shifts and checks if ''$1''
|
|
still expands to something, using the [[commands:classictest | test command]]:
|
|
|
|
<code>
|
|
while [ "$1" ]
|
|
do
|
|
echo "$1"
|
|
shift
|
|
done
|
|
</code>
|
|
|
|
Looks nice, but has the disadvantage of stopping when ''$1'' is empty
|
|
(null-string). Let's modify it to run as long as ''$1'' is defined
|
|
(but may be null), using [[syntax:pe#use_an_alternate_value | parameter expansion for an alternate value]]:
|
|
|
|
<code>
|
|
while [ "${1+defined}" ]; do
|
|
echo "$1"
|
|
shift
|
|
done
|
|
</code>
|
|
|
|
==== Getopts ====
|
|
|
|
There is a [[howto:getopts_tutorial|small tutorial dedicated to ''getopts'']] (//under construction//).
|
|
|
|
===== Mass usage =====
|
|
|
|
==== All Positional Parameters ====
|
|
|
|
Sometimes it's necessary to just "relay" or "pass" given
|
|
arguments to another program. It's very inefficient to do that in one
|
|
of these loops, as you will destroy integrity, most likely
|
|
(spaces!).
|
|
|
|
The shell developers created ''$*'' and ''$@'' for this purpose.
|
|
|
|
As overview:
|
|
|
|
^Syntax ^Effective result ^
|
|
| ''$*'' | ''$1 $2 $3 ... ${N}'' |
|
|
| ''$@'' | ''$1 $2 $3 ... ${N}'' |
|
|
| ''"$*"'' | ''"$1c$2c$3c...c${N}"'' |
|
|
| ''"$@"'' | ''"$1" "$2" "$3" ... "${N}"'' |
|
|
|
|
Without being quoted (double quotes), both have the same
|
|
effect: All positional parameters from ''$1'' to the last one used are
|
|
expanded without any special handling.
|
|
|
|
When the ''$*'' special parameter is double quoted, it expands to the
|
|
equivalent of: ''"$1c$2c$3c$4c........$N"'', where 'c' is the first
|
|
character of ''IFS''.
|
|
|
|
But when the ''$@'' special parameter is used inside double quotes, it
|
|
expands to the equivanent of...
|
|
|
|
''"$1" "$2" "$3" "$4" ..... "$N"''
|
|
|
|
...which **reflects all positional parameters as they were
|
|
set initially** and passed to the script or function. If you want
|
|
to re-use your positional parameters to **call another program** (for
|
|
example in a wrapper-script), then this is the choice for you, use
|
|
double quoted ''"$@"''.
|
|
|
|
Well, let's just say: **You almost always want a quoted ''"$@"''!**
|
|
|
|
==== Range Of Positional Parameters ====
|
|
|
|
Another way to mass expand the positional parameters is similar to
|
|
what is possible for a range of characters using
|
|
[[syntax:pe#substring_expansion | substring expansion]] on normal
|
|
parameters and the mass expansion range of [[syntax:arrays | arrays]].
|
|
|
|
''${@:START:COUNT}''
|
|
|
|
''${*:START:COUNT}''
|
|
|
|
''"${@:START:COUNT}"''
|
|
|
|
''"${*:START:COUNT}"''
|
|
|
|
The rules for using ''@'' or ''*'' and quoting are the same as
|
|
above. This will expand ''COUNT'' number of positional parameters
|
|
beginning at ''START''. ''COUNT'' can be omitted (''${@:START}''), in
|
|
which case, all positional parameters beginning at ''START'' are
|
|
expanded.
|
|
|
|
If ''START'' is negative, the positional parameters are numbered in reverse
|
|
starting with the last one.
|
|
|
|
''COUNT'' may not be negative, i.e. the element count may not be decremented.
|
|
|
|
__**Example:**__
|
|
START at the last positional parameter:
|
|
<code>
|
|
echo "${@: -1}"
|
|
</code>
|
|
|
|
__**Attention**__: As of Bash 4, a ''START'' of ''0'' includes the special parameter ''$0'', i.e. the shell name or whatever $0 is set to, when the positional parameters are in use. A ''START'' of ''1'' begins at ''$1''. In Bash 3 and older, both ''0'' and ''1'' began at ''$1''.
|
|
|
|
===== Setting Positional Parameters =====
|
|
|
|
Setting positional parameters with command line arguments,
|
|
is not the only way to set them.
|
|
The [[ commands:builtin:set | builtin command, set ]]
|
|
may be used to "artificially" change the positional parameters from
|
|
inside the script or function:
|
|
|
|
<code>
|
|
set "This is" my new "set of" positional parameters
|
|
|
|
# RESULTS IN
|
|
# $1: This is
|
|
# $2: my
|
|
# $3: new
|
|
# $4: set of
|
|
# $5: positional
|
|
# $6: parameters
|
|
</code>
|
|
|
|
It's wise to signal "end of options" when setting positional
|
|
parameters this way. If not, the dashes might be interpreted as an option switch
|
|
by ''set'' itself:
|
|
|
|
<code>
|
|
# both ways work, but behave differently. See the article about the set command!
|
|
set -- ...
|
|
set - ...
|
|
</code>
|
|
|
|
Alternately this will also preserve any verbose (-v) or tracing (-x) flags, which may otherwise be reset by ''set''
|
|
<code>
|
|
set -$- ...
|
|
</code>
|
|
|
|
FIXME continue
|
|
|
|
===== Production examples =====
|
|
|
|
==== Using a while loop ====
|
|
|
|
To make your program accept options as standard command syntax:
|
|
|
|
''COMMAND [options] <params>'' # Like 'cat -A file.txt'
|
|
|
|
See simple option parsing code below. It's not that flexible. It
|
|
doesn't auto-interpret combined options (-fu USER) but it works and is
|
|
a good rudimentary way to parse your arguments.
|
|
|
|
<code>
|
|
#!/bin/sh
|
|
# Keeping options in alphabetical order makes it easy to add more.
|
|
|
|
while :
|
|
do
|
|
case "$1" in
|
|
-f | --file)
|
|
file="$2" # You may want to check validity of $2
|
|
shift 2
|
|
;;
|
|
-h | --help)
|
|
display_help # Call your function
|
|
# no shifting needed here, we're done.
|
|
exit 0
|
|
;;
|
|
-u | --user)
|
|
username="$2" # You may want to check validity of $2
|
|
shift 2
|
|
;;
|
|
-v | --verbose)
|
|
# It's better to assign a string, than a number like "verbose=1"
|
|
# because if you're debugging the script with "bash -x" code like this:
|
|
#
|
|
# if [ "$verbose" ] ...
|
|
#
|
|
# You will see:
|
|
#
|
|
# if [ "verbose" ] ...
|
|
#
|
|
# Instead of cryptic
|
|
#
|
|
# if [ "1" ] ...
|
|
#
|
|
verbose="verbose"
|
|
shift
|
|
;;
|
|
--) # End of all options
|
|
shift
|
|
break;
|
|
-*)
|
|
echo "Error: Unknown option: $1" >&2
|
|
exit 1
|
|
;;
|
|
*) # No more options
|
|
break
|
|
;;
|
|
esac
|
|
done
|
|
|
|
# End of file
|
|
</code>
|
|
|
|
==== Filter unwanted options with a wrapper script ====
|
|
|
|
This simple wrapper enables filtering unwanted options (here: ''-a''
|
|
and ''--all'' for ''ls'') out of the command line. It reads the
|
|
positional parameters and builds a filtered array consisting of them, then
|
|
calls ''ls'' with the new option set. It also respects the ''--''
|
|
as "end of options" for ''ls'' and doesn't change anything after it:
|
|
|
|
<code>
|
|
#!/bin/bash
|
|
|
|
# simple ls(1) wrapper that doesn't allow the -a option
|
|
|
|
options=() # the buffer array for the parameters
|
|
eoo=0 # end of options reached
|
|
|
|
while [[ $1 ]]
|
|
do
|
|
if ! ((eoo)); then
|
|
case "$1" in
|
|
-a)
|
|
shift
|
|
;;
|
|
--all)
|
|
shift
|
|
;;
|
|
-[^-]*a*|-a?*)
|
|
options+=("${1//a}")
|
|
shift
|
|
;;
|
|
--)
|
|
eoo=1
|
|
options+=("$1")
|
|
shift
|
|
;;
|
|
*)
|
|
options+=("$1")
|
|
shift
|
|
;;
|
|
esac
|
|
else
|
|
options+=("$1")
|
|
|
|
# Another (worse) way of doing the same thing:
|
|
# options=("${options[@]}" "$1")
|
|
shift
|
|
fi
|
|
done
|
|
|
|
/bin/ls "${options[@]}"
|
|
</code>
|
|
|
|
==== Using getopts ====
|
|
|
|
There is a [[howto:getopts_tutorial|small tutorial dedicated to ''getopts'']] (//under construction//).
|
|
|
|
===== See also =====
|
|
|
|
* Internal: [[howto:getopts_tutorial]]
|
|
* Internal: [[syntax:ccmd:while_loop]]
|
|
* Internal: [[syntax:ccmd:c_for]]
|
|
* Internal: [[syntax:arrays]] (for equivalent syntax for mass-expansion)
|
|
* Internal: [[syntax:pe#substring_expansion | Substring expansion on a parameter]] (for equivalent syntax for mass-expansion)
|
|
* Dictionary, internal: [[dict:terms:parameter]]
|
|
</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="scripting/posparams.txt">scripting/posparams.txt</span></li><li><span class="iconify text-muted" data-icon="mdi:calendar"></span> Last modified: <span title="2018/05/12 18:04">2018/05/12 18:04</span></li><li class="text-muted">by <bdi>wayeoyuz</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/20220925044221/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/20220925044221js_/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/20220925044221im_/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/20220925044221/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/20220925044221im_/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/20220925044221/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/20220925044221im_/https://wiki.bash-hackers.org/lib/exe/indexer.php?id=scripting%3Aposparams&1664080954" width="2" height="1" alt=""/>
|
|
</div>
|
|
|
|
</body>
|
|
</html>
|
|
<!--
|
|
FILE ARCHIVED ON 04:42:21 Sep 25, 2022 AND RETRIEVED FROM THE
|
|
INTERNET ARCHIVE ON 11:35:24 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: 145.875
|
|
exclusion.robots: 0.211
|
|
exclusion.robots.policy: 0.195
|
|
RedisCDXSource: 1.538
|
|
esindex: 0.01
|
|
LoadShardBlock: 116.957 (3)
|
|
PetaboxLoader3.datanode: 111.897 (4)
|
|
load_resource: 96.671
|
|
PetaboxLoader3.resolve: 68.617
|
|
--> |