197 lines
4.8 KiB
HTML
197 lines
4.8 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//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="text/html; charset=iso-8859-1">
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<link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 -->
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<!-- Copyright (c) 2001 The Open Group, All Rights Reserved -->
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<title>break</title>
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</head>
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<body bgcolor="white">
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<basefont size="3"> <a name="break"></a> <a name="tag_04_11"></a><!-- break -->
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<!--header start-->
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<center><font size="2">The Open Group Base Specifications Issue 6<br>
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IEEE Std 1003.1-2001<br>
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Copyright © 2001 The IEEE and The Open Group, All Rights reserved.</font></center>
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<!--header end-->
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<hr size="2" noshade>
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<h4><a name="tag_04_11_01"></a>NAME</h4>
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<blockquote>break - exit from for, while, or until loop</blockquote>
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<h4><a name="tag_04_11_02"></a>SYNOPSIS</h4>
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<blockquote class="synopsis">
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<p><code><tt>break</tt> <b>[</b><i>n</i><b>]</b></code></p>
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</blockquote>
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<h4><a name="tag_04_11_03"></a>DESCRIPTION</h4>
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<blockquote>
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<p>The <i>break</i> utility shall exit from the smallest enclosing <b>for</b>, <b>while</b>, or <b>until</b> loop, if any; or from
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the <i>n</i>th enclosing loop if <i>n</i> is specified. The value of <i>n</i> is an unsigned decimal integer greater than or equal
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to 1. The default shall be equivalent to <i>n</i>=1. If <i>n</i> is greater than the number of enclosing loops, the outermost
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enclosing loop shall be exited. Execution shall continue with the command immediately following the loop.</p>
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</blockquote>
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<h4><a name="tag_04_11_04"></a>OPTIONS</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_04_11_05"></a>OPERANDS</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_04_11_06"></a>STDIN</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_04_11_07"></a>INPUT FILES</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_04_11_08"></a>ENVIRONMENT VARIABLES</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_04_11_09"></a>ASYNCHRONOUS EVENTS</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_04_11_10"></a>STDOUT</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_04_11_11"></a>STDERR</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_04_11_12"></a>OUTPUT FILES</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_04_11_13"></a>EXTENDED DESCRIPTION</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_04_11_14"></a>EXIT STATUS</h4>
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<blockquote>
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<dl compact>
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<dt> 0</dt>
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<dd>Successful completion.</dd>
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<dt>>0</dt>
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<dd>The <i>n</i> value was not an unsigned decimal integer greater than or equal to 1.</dd>
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</dl>
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</blockquote>
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<h4><a name="tag_04_11_15"></a>CONSEQUENCES OF ERRORS</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<hr>
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<div class="box"><em>The following sections are informative.</em></div>
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<h4><a name="tag_04_11_16"></a>APPLICATION USAGE</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_04_11_17"></a>EXAMPLES</h4>
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<blockquote>
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<pre>
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<tt>for i in * do
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if test -d "$i" then break fi done
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</tt>
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</pre>
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</blockquote>
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<h4><a name="tag_04_11_18"></a>RATIONALE</h4>
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<blockquote>
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<p>In early proposals, consideration was given to expanding the syntax of <i>break</i> and <a href=
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"../utilities/continue.html"><i>continue</i></a> to refer to a label associated with the appropriate loop as a preferable
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alternative to the <i>n</i> method. However, this volume of IEEE Std 1003.1-2001 does reserve the name space of command
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names ending with a colon. It is anticipated that a future implementation could take advantage of this and provide something
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like:</p>
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<pre>
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<tt>outofloop: for i in a b c d e
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do
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for j in 0 1 2 3 4 5 6 7 8 9
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do
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if test -r "${i}${j}"
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then break outofloop
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fi
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done
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done
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</tt>
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</pre>
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<p>and that this might be standardized after implementation experience is achieved.</p>
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</blockquote>
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<h4><a name="tag_04_11_19"></a>FUTURE DIRECTIONS</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_04_11_20"></a>SEE ALSO</h4>
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<blockquote>
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<p><a href="xcu_chap02.html#tag_02_14"><i>Special Built-In Utilities</i></a></p>
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</blockquote>
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<h4><a name="tag_04_11_21"></a>CHANGE HISTORY</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<div class="box"><em>End of informative text.</em></div>
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<hr>
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UNIX ® is a registered Trademark of The Open Group.<br>
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POSIX ® is a registered Trademark of The IEEE.<br>
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[ <a href="../mindex.html">Main Index</a> | <a href="../basedefs/contents.html">XBD</a> | <a href=
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"../utilities/contents.html">XCU</a> | <a href="../functions/contents.html">XSH</a> | <a href="../xrat/contents.html">XRAT</a>
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