You don't because system starts a synchronous child process (e.g. perl starts "PMEMD" and then waits for it to exit before continuing). If you want to create a separate simultaneous child process you need to either use bare fork and exec yourself or look into a module such as IPC::Run or the like.

Update: And before someone else brings it up, yes on *NIX-ish OSen you can append an & to the command line you send to system and get the process backgrounded. But that's just asking for pain (especially since the OP wants the child's pid yadda yadda).

The cake is a lie.
The cake is a lie.
The cake is a lie.

In reply to Re: How to monitor a child process from a perl script by Fletch
in thread How to monitor a child process from a perl script by oscarjiao

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