52 lines
1.5 KiB
HTML
52 lines
1.5 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
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<html>
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<head>
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<meta name="generator" content="HTML Tidy, see www.w3.org">
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<meta http-equiv="Content-Type" content=
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"text/html; charset=utf-8">
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<title>Command substitutions</title>
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<LINK rel="stylesheet" type="text/css" href="../rzahg/ic.css">
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</HEAD>
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<body bgcolor="#FFFFFF">
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<!-- Java sync-link -->
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<SCRIPT LANGUAGE="Javascript" SRC="../rzahg/synch.js" TYPE="text/javascript"></SCRIPT>
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<h2>Command substitutions</h2>
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<p>Command substitution allows the output of a command to be
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substituted in place of the command name itself. Command
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substitution occurs when the command is enclosed as follows:</p>
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<p>$(<em>command</em>)</p>
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<p>or by using backquotes:</p>
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<p>`<em>command</em>`</p>
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<p>The backquoted version is provided for compatibility. Its use is
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discouraged.</p>
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<p>The shell expands the command substitution by running <em>
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command</em> in a subshell environment and replacing the command
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substitution with the standard output of the <em>command</em>,
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removing sequences of one or more <newline>s at the end of
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the substitution. Embedded <newline>s before the end of the
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output are not removed; however, during field splitting, they may
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be translated into <space>s, depending on the value of the
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<strong>IFS</strong> variable and quoting that is in effect.</p>
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<p><strong>Examples</strong></p>
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<ol>
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<li>Set the variable list to the output of the ls command:
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<pre>
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list=$(ls)
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</pre>
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</li>
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</ol>
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</body>
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</html>
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