83 lines
2.8 KiB
HTML
83 lines
2.8 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>Lists</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>Lists</h2>
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<p>A list is a sequence of commands separated by an ampersand
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(<strong>&</strong>) or a semicolon (<strong>;</strong>), and
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optionally terminated by a <newline>, ampersand, or
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semicolon. An AND-OR list is a sequence of commands separated by a
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<strong>&&</strong> or <strong>||</strong>. Both operators
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have the same priority.</p>
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<p><strong>Asynchronous lists</strong></p>
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<p>If a command is terminated by the control operator ampersand
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(<strong>&</strong>), <strong>qsh</strong> runs the command
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asynchronously. That is, <strong>qsh</strong> does not wait for the
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command to finish before running the next command. The format for
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running a command in the background is:</p>
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<p><em>command1</em> <strong>&</strong> [ <em>command2</em>
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<strong>&</strong> ... ]</p>
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<p>If the interactive option is not set, the standard input of any
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asynchronous command is set to /dev/qsh-stdin-null. The exit status
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of an asynchronous list is the exit status of the last <em>
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command</em>.</p>
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<p><strong>Sequential lists</strong></p>
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<p>Commands that are separated by a semicolon (<strong>;</strong>)
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are run sequentially. The format for a sequential list is:</p>
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<p><em>command1</em> [ <strong>;</strong> <em>command2</em> ...
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]</p>
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<p>The commands in the list are run in the order they are written.
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The exit status of a sequential list is the exit status of the last
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<em>command</em>.</p>
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<p><strong>AND lists</strong></p>
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<p>The format for an AND list is:</p>
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<p><em>command1</em> [ <strong>&&</strong> <em>
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command2</em> ... ]</p>
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<p>With an AND list, <strong>qsh</strong> runs <em>command1</em>,
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and then runs <em>command2</em> if the exit status of the <em>
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command1</em> is zero and so on until a command has a non-zero exit
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status or there are no commands left to run. The exit status of an
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AND list is the exit status of the last <em>command</em> that is
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run.</p>
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<p><strong>OR lists</strong></p>
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<p>The format for an OR list is:</p>
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<p><em>command1</em> [ <strong>||</strong> <em>command2</em> ...
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]</p>
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<p>With an OR list, <strong>qsh</strong> runs <em>command1</em>,
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and then runs <em>command2</em> if the exit status of the <em>
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command1</em> is non-zero and so on until a command has a zero exit
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status or there are no commands left to run. The exit status of an
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OR list is the exit status of the last <em>command</em> that is
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run.</p>
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</body>
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</html>
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