82 lines
2.9 KiB
HTML
82 lines
2.9 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 language</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 language</h2>
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<p><strong>qsh</strong> is a program that:</p>
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<ul>
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<li>reads input from either a file or a terminal</li>
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<li>breaks the input into tokens</li>
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<li>parses the input into simple and compound commands</li>
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<li>performs various expansions on each command</li>
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<li>performs redirection of input and output</li>
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<li>runs the commands</li>
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<li>optionally waits for the commands to complete</li>
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</ul>
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<p><strong>qsh</strong> implements a command language that has flow
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control constructs, variables, and functions. The interpretative
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language is common to both interactive and non-interactive use
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(shell scripts). So the same commands that are entered at an
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interactive command line can also be put in a file and the file can
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be run directly by <strong>qsh</strong>.</p>
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<p>For more information about particular features of <strong>
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qsh</strong>, see the following topics:</p>
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<blockquote>
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<p><strong><a href="quoting.htm">Quoting</a></strong><br>
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Select this link to view information about quoting, including the escape
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character, literal quotes, and grouping quotes.</p>
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<p><strong><a href="params.htm">Parameters</a></strong><br>
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Select this link to view information about parameters, including positional
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parameters and special parameters.</p>
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<p><strong><a href="variable.htm">Variables</a></strong><br>
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Select this link to view information about variables, including the variables set by
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and variables used by <strong>qsh</strong>.</p>
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<p><strong><a href="wordexp.htm">Word expansions</a></strong><br>
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Select this link to view information about word expansions, including tilde expansion,
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parameter expansion, command substitution, arithmetic expansion, field splitting, path name
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expansion, and quote removal.</p>
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<p><strong><a href="redirect.htm">Redirection</a></strong><br>
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Select this link to view information about input and output redirections.</p>
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<p><strong><a href="simpcmds.htm">Simple commands</a></strong><br>
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Select this link to view information about running simple commands.</p>
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<p><strong><a href="pipeline.htm">Pipelines</a></strong><br>
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Select this link to view information about running multiple commands in a pipeline.</p>
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<p><strong><a href="lists.htm">Lists</a></strong><br>
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Select this link to view information about running multiple commands in a list.</p>
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<p><strong><a href="cmpdcmds.htm">Compound commands</a></strong><br>
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Select this link to view information about compound commands, including grouping
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commands, conditional commands, loop commands, and functions.
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</p></blockquote>
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</body>
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</html>
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