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Old 05-06-2014, 03:56 PM   #1
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auto-creating a pid file when starting a process

I'm running ffmpeg-2.1.4-1 on a fedora 20 web server
I start ffmpeg by running a single (long) command in the console and I usually either put a '&' on the end to background it or I run it in a screen and then detach. It's not started by /etc/init.d/blah-de-blah. Is there a way to make ffmpeg create a pid file when it's started? ie: /var/run/ or similar.
I see from digging around that ffmpeg creates a pid but it's a number which changes every time ffmpeg is started.
To create a pid file do I need to modify the ffmpeg command? or does it have to be done by a script? I have seen a few script examples on google but they all refer to the /etc/init.d/program start method and don't fit a single command scenario. Thanks for any help.
Old 05-06-2014, 06:54 PM   #2
DJ Shaji
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you can use "pidof " to find the pid of any running program. So you can do "ffmpeg <some options> & pidof ffmpeg > /tmp/"
Old 05-06-2014, 08:19 PM   #3
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nohup sleep 30 & echo $! > pidfile
Substitute your ffmpeg command for "sleep 30" in the example above.
Old 05-07-2014, 06:02 AM   #4
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@DJ: thankyou for your advice DJ, your suggestion worked, ffmpeg is now creating a pid file.

Last edited by tonj; 05-07-2014 at 06:56 AM.
Old 05-09-2014, 10:06 AM   #5
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Note: the pidof can list multiple process numbers if there are multiple instances of the application running. It does not indicate WHICH one is the one you just started.

Only the solution in post #3 will do that, as only the shell knows what the pid was of the process it just started.
Old 05-09-2014, 04:36 PM   #6
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Please set this thread as solved - thx


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