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    <title>s6-portable-utils: the s6-test program</title>
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<p>
<a href="index.html">s6-portable-utils</a><br />
<a href="http://skarnet.org/software/">Software</a><br />
<a href="http://skarnet.org/">skarnet.org</a>
</p>

<h1> The <tt>s6-test</tt> program </h1>

<p>
 s6-test evaluates an expression and indicates the result via its
exit status.
</p>

<h2> Interface </h2>

<pre>
     s6-test <em>expression...</em>
</pre>

<p>
 s6-test acts as the generic
<a href="http://pubs.opengroup.org/onlinepubs/9699919799/utilities/test.html">test</a> utility,
but it diverges from the specification on one point: if an argument starts with a backslash,
this backslash is ignored (and the argument cannot be an operation). This is a simple
disambiguation technique that has unfortunately not been chosen by the standard.
</p>

<p>
 s6-test accepts an arbitrary number of arguments.
</p>

<h2> Posixness </h2>

<p>
 s6-test <strong>is not</strong> suitable as a Single Unix
<a href="http://pubs.opengroup.org/onlinepubs/9699919799/utilities/test.html">test</a>
program; however, if your arguments never start with a backslash, it exhibits the
exact same behaviour.
</p>

<h2> Non-standard expressions </h2>

<ul>
 <li> <tt>-v&nbsp;<em>VAR</em></tt>&nbsp;: tests whether the
<em>VAR</em> variable is defined in the current environment. </li>
</ul>

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