85 lines
1.7 KiB
HTML
85 lines
1.7 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>If command</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>If command</h2>
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<p>The syntax of the <strong>if</strong> command is</p>
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<p><strong>if</strong> <em>list1</em></p>
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<p><strong>then</strong> <em>list2</em></p>
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<p><strong>[</strong> <strong>elif</strong> <em>list3</em></p>
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<p><strong>then</strong> <em>list4</em> <strong>]</strong> ...</p>
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<p><strong>[</strong> <strong>else</strong> <em>list5</em> <strong>
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]</strong></p>
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<p><strong>fi</strong></p>
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<p>First, <strong>qsh</strong> runs <em>list1</em> and if its exit
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status is zero then <strong>qsh</strong> runs <em>list2</em>.
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Otherwise, each elif <em>list3</em> is run and if its exit status
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is zero then <strong>qsh</strong> runs <em>list4</em>. Otherwise,
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<strong>qsh</strong> runs <em>list5</em>.</p>
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<p><strong>Examples</strong></p>
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<ol>
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<li>An if-then-fi command.
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<pre>
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x=4
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y=9
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if test $x -lt $y
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then
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echo $x is less than $y
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fi
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</pre>
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</li>
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<li>An if-then-else-fi command.
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<pre>
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x=10
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y=9
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if test $x -lt $y
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then
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echo echo $x is less than $y
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else
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echo echo $x is greater than or equal to $y
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fi
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</pre>
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</li>
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<li>An if-then-elif-else-fi command.
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<pre>
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x=4
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y=4
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if test $x -lt $y
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then
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echo echo $x is less than $y
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elif test $x -eq $y
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then
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echo $x is equal to $y
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else
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echo $x is greater than or equal to $y
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fi
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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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