ibm-information-center/dist/eclipse/plugins/i5OS.ic.rzahz_5.4.0.1/perform.htm

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<title>Performance considerations</title>
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<h2>Performance considerations</h2>
<p>The following tips can help improve performance when using <strong>qsh</strong>.</p>
<ul>
<li>Do not use command substitutions in the value of the <strong>
PS1</strong> variable. This causes a new process to be started
every time you press the &lt;enter&gt; key.<p></li>
<li>Use input redirection instead of cat. For example, the
following command:
<pre>
cat myfile | grep Hello
</pre>
<p>can be replaced with this command:</p>
<pre>
grep Hello &lt; myfile
</pre>
</li>
<li>Use built-in utilities whenever possible because they are run
in the current process.<p></li>
<li>Leave the <strong>SHELL</strong> variable unset. If a script
file does not contain a "#!" on the first line, the script is run
in the current activation of <strong>qsh</strong>.<p></li>
</ul>
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