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<H3><A NAME="SECTION0082127000000000000000"></A><A NAME="optparse-printing-version-string"></A>
<BR>
6.21.2.7 Printing a version string
</H3>

<P>
Similar to the brief usage string, <tt class="module">optparse</tt> can also print a version string
for your program.  You have to supply the string as the <code>version</code>
argument to OptionParser:
<div class="verbatim"><pre>
parser = OptionParser(usage="%prog [-f] [-q]", version="%prog 1.0")
</pre></div>

<P>
Note that <code>"%prog"</code> is expanded just like it is in <code>usage</code>.  Apart
from that, <code>version</code> can contain anything you like.  When you supply
it, <tt class="module">optparse</tt> automatically adds a <code>"-version"</code> option to your parser.
If it encounters this option on the command line, it expands your
<code>version</code> string (by replacing <code>"%prog"</code>), prints it to stdout, and
exits.

<P>
For example, if your script is called <code>/usr/bin/foo</code>:
<div class="verbatim"><pre>
$ /usr/bin/foo --version
foo 1.0
</pre></div>

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<span class="release-info">Release 2.4.2, documentation updated on 28 September 2005.</span>
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