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<title>execline: the background command</title>
<meta name="Description" content="execline: the background command" />
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<p>
<a href="index.html">execline</a><br />
<a href="http://skarnet.org/software/">Software</a><br />
<a href="http://skarnet.org/">skarnet.org</a>
</p>
<h1> The <tt>background</tt> program </h1>
<tt>background</tt> launches a command in the background, then goes on
with the execution flow.
<h2> Interface </h2>
<p>
In an <a href="execlineb.html">execlineb</a> script:
</p>
<pre>
background [ -d ] { <em>prog1...</em> } <em>prog2...</em>
</pre>
<ul>
<li> <tt>background</tt> reads a <em>prog1...</em> command in a
<a href="el_semicolon.html">block</a> and unquotes it. </li>
<li> It spawns a child executing <em>prog1...</em>. </li>
<li> It sets the <tt>!</tt> environment
variable to the pid of the <em>prog1...</em> process. </li>
<li> It then execs into <em>prog2...</em>. </li>
</ul>
<h2> Options </h2>
<ul>
<li> <tt>-d</tt> : doublefork. If the <tt>-d</tt> option is set,
<em>prog1...</em> will run as a grandchild of <tt>background</tt>. </li>
</ul>
<h2> Notes </h2>
<ul>
<li> <tt>background <em>prog1...</em> "" <em>prog2...</em></tt> is
equivalent to <tt>sh -c '<em>prog1...</em> & ; exec <em>prog2...</em>'</tt>. </li>
</ul>
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