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copied!<p>What he meant is that <strong>job control is by default turned off in non-interactive mode</strong> (i.e. in a script.)</p> <p>From the <code>bash</code> man page:</p> <pre><code>JOB CONTROL Job control refers to the ability to selectively stop (suspend) the execution of processes and continue (resume) their execution at a later point. A user typically employs this facility via an interactive interface supplied jointly by the system’s terminal driver and bash. </code></pre> <p>and</p> <pre><code> set [--abefhkmnptuvxBCHP] [-o option] [arg ...] ... -m Monitor mode. Job control is enabled. This option is on by default for interactive shells on systems that support it (see JOB CONTROL above). Background processes run in a separate process group and a line containing their exit status is printed upon their completion. </code></pre> <p>When he said "is stupid" he meant that not only:</p> <ol> <li>is job control <em>meant</em> mostly for facilitating interactive control (whereas a script can work directly with the pid's), but also</li> <li>I quote his original answer, <em>... relies on the fact that you didn't start any other jobs previously in the script which is a bad assumption to make</em>. Which is quite correct.</li> </ol> <p><strong>UPDATE</strong></p> <p>In answer to your comment: yes, nobody will stop you from using job control in your bash script -- there is no hard case for <em>forcefully disabling</em> <code>set -m</code> (i.e. yes, job control from the script will work if you want it to.) Remember that in the end, especially in scripting, there always are more than one way to skin a cat, but some ways are more portable, more reliable, make it simpler to handle error cases, parse the output, etc.</p> <p>You particular circumstances may or may not warrant a way different from what <code>lhunath</code> (and other users) deem "best practices".</p>

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