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<title>getopts - Process single-character switches with switch clustering</title>
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<h1><a>getopts - Process single-character switches with switch clustering</a></h1>
<p><a name="__index__"></a></p>

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<ul>

	<li><a href="#name">NAME</a></li>
	<li><a href="#synopsis">SYNOPSIS</a></li>
	<li><a href="#description">DESCRIPTION</a></li>
	<li><a href="#help_and_version"><code>-help</code> and <code>-version</code></a></li>
</ul>
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<h1><a name="name">NAME</a></h1>
<p>getopt, getopts - Process single-character switches with switch clustering</p>
<p>
</p>
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<h1><a name="synopsis">SYNOPSIS</a></h1>
<pre>
    <span class="keyword">use</span> <span class="variable">Getopt::Std</span><span class="operator">;</span>
</pre>
<pre>
    <span class="variable">getopt</span><span class="operator">(</span><span class="string">'oDI'</span><span class="operator">);</span>    <span class="comment"># -o, -D &amp; -I take arg.  Sets $opt_* as a side effect.</span>
    <span class="variable">getopt</span><span class="operator">(</span><span class="string">'oDI'</span><span class="operator">,</span> <span class="operator">\</span><span class="variable">%opts</span><span class="operator">);</span>    <span class="comment"># -o, -D &amp; -I take arg.  Values in %opts</span>
    <span class="variable">getopts</span><span class="operator">(</span><span class="string">'oif:'</span><span class="operator">);</span>  <span class="comment"># -o &amp; -i are boolean flags, -f takes an argument</span>
                      <span class="comment"># Sets $opt_* as a side effect.</span>
    <span class="variable">getopts</span><span class="operator">(</span><span class="string">'oif:'</span><span class="operator">,</span> <span class="operator">\</span><span class="variable">%opts</span><span class="operator">);</span>  <span class="comment"># options as above. Values in %opts</span>
</pre>
<p>
</p>
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<h1><a name="description">DESCRIPTION</a></h1>
<p>The <code>getopt()</code> function processes single-character switches with switch
clustering.  Pass one argument which is a string containing all switches
that take an argument.  For each switch found, sets $opt_x (where x is the
switch name) to the value of the argument if an argument is expected,
or 1 otherwise.  Switches which take an argument don't care whether
there is a space between the switch and the argument.</p>
<p>The <code>getopts()</code> function is similar, but you should pass to it the list of all
switches to be recognized.  If unspecified switches are found on the
command-line, the user will be warned that an unknown option was given.</p>
<p>Note that, if your code is running under the recommended <code>use strict
'vars'</code> pragma, you will need to declare these package variables
with &quot;our&quot;:</p>
<pre>
    <span class="keyword">our</span><span class="operator">(</span><span class="variable">$opt_x</span><span class="operator">,</span> <span class="variable">$opt_y</span><span class="operator">);</span>
</pre>
<p>For those of you who don't like additional global variables being created, <code>getopt()</code>
and <code>getopts()</code> will also accept a hash reference as an optional second argument. 
Hash keys will be x (where x is the switch name) with key values the value of
the argument or 1 if no argument is specified.</p>
<p>To allow programs to process arguments that look like switches, but aren't,
both functions will stop processing switches when they see the argument
<code>--</code>.  The <code>--</code> will be removed from @ARGV.</p>
<p>
</p>
<hr />
<h1><a name="help_and_version"><code>--help</code> and <code>--version</code></a></h1>
<p>If <code>-</code> is not a recognized switch letter, <code>getopts()</code> supports arguments
<code>--help</code> and <code>--version</code>.  If <code>main::HELP_MESSAGE()</code> and/or
<code>main::VERSION_MESSAGE()</code> are defined, they are called; the arguments are
the output file handle, the name of option-processing package, its version,
and the switches string.  If the subroutines are not defined, an attempt is
made to generate intelligent messages; for best results, define $main::VERSION.</p>
<p>If embedded documentation (in pod format, see <a href="../../lib/Pod/perlpod.html">the perlpod manpage</a>) is detected
in the script, <code>--help</code> will also show how to access the documentation.</p>
<p>Note that due to excessive paranoia, if $Getopt::Std::STANDARD_HELP_VERSION
isn't true (the default is false), then the messages are printed on STDERR,
and the processing continues after the messages are printed.  This being
the opposite of the standard-conforming behaviour, it is strongly recommended
to set $Getopt::Std::STANDARD_HELP_VERSION to true.</p>
<p>One can change the output file handle of the messages by setting
$Getopt::Std::OUTPUT_HELP_VERSION.  One can print the messages of <code>--help</code>
(without the <code>Usage:</code> line) and <code>--version</code> by calling functions <code>help_mess()</code>
and <code>version_mess()</code> with the switches string as an argument.</p>

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