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<title>execline: the elgetpositionals command</title>
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<p>
<a href="index.html">execline</a><br />
<a href="http://skarnet.org/software/">Software</a><br />
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<h1> The <tt>elgetpositionals</tt> program </h1>
<p>
<tt>elgetpositionals</tt> substitutes the positional parameters of an execline script.
</p>
<h2> Interface </h2>
<pre>
elgetpositionals [ -P <em>sharp</em> ] <em>prog...</em>
</pre>
<ul>
<li> <tt>elgetpositionals</tt> reads the number <em>n</em> of "positional
parameters" in the <tt>#</tt> environment variable. If that variable
is not set or does not contain a valid <em>n</em>, <tt>elgetpositionals</tt>
exits 100. </li>
<li> <tt>elgetpositionals</tt> performs some
<a href="el_substitute.html">substitutions</a> in parallel on
<em>prog...</em>:
<ul>
<li> key: <tt>#</tt>, value: <em>n</em> </li>
<li> key: <tt>0</tt>, value: the value of the <tt>0</tt> environment
variable </li>
<li> key: <tt>1</tt>, value: the value of the <tt>1</tt> environment
variable </li>
<li> ... and so on until <em>n</em> (or <em>sharp</em> if it is
greater than <em>n</em>). Those values are never transformed. </li>
<li> key: <tt>@</tt>, value: all values of the variables from <tt>1</tt> to
<tt><em>n</em></tt>. This value is <a href="el_transform.html#split">split</a>
into <em>n</em> words. </li>
</ul>
If a variable between <tt>0</tt> and <tt><em>n</em></tt> does not
exist, <tt>elgetpositionals</tt> exits 100.
</li>
</ul>
<h2> Options </h2>
<ul>
<li> <tt>-P</tt> <em>sharp</em> : substitute at least
<em>sharp</em>+1 positional parameters, from 0 to
max(<em>n</em>, <em>sharp</em>). If <em>n</em><<em>sharp</em>,
positional parameters between <em>n</em>+1 and <em>sharp</em> are
replaced with the empty string. Not having the <tt>-P</tt> switch is
equivalent to having <tt>-P 0</tt>. </li>
</ul>
<h2> Notes </h2>
<ul>
<li> A typical argument-taking execline script will
often begin that way:
<pre>
#!/command/execlineb
elgetopt <em>optstring</em>
elgetpositionals
<em>prog...</em>
</pre>
</li>
<li> If you are performing other substitutions that do not depend
on the positional parameters, think about replacing the
<tt>elgetpositionals</tt> call with a
<a href="multisubstitute.html">multisubstitute</a> call containing
the <tt>elgetpositionals</tt> directive. </li>
<li> If you are going to use the <a href="shift.html">shift</a>
command, it is best to use <a href="importas.html">importas</a> to
substitute the first positional parameters, then use <tt>shift</tt>,
then <tt>elgetpositionals</tt>. That way, <tt>$@</tt> will correctly
be replaced by the remaining arguments. More generally, you should
try to use <tt>elgetpositionals</tt> as late as possible. </li>
<li> Use <tt>execlineb</tt>'s <tt>-S</tt> switch instead of
<tt>elgetpositionals</tt> whenever you can. It is more efficient. </li>
</ul>
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