Unix .pid file created automatically?

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Reference for proper handling of PID file on Unix

Is the .pid file in unix created automatically by the operating system whenever a process runs OR should the process create a .pid file programmatically like "echo $$ > myprogram.pid" ?

See http://stackoverflow.com/questions/688343/reference-for-proper-handling-of-pid-file-on-unix — tamasgal, Sep 21 '12 at 07:12

nneonneo · Accepted Answer · 2012-09-21T07:18:40.560

1

The latter holds true -- a process must create the .pid file (the OS won't do it). pid files are often used by daemon processes for various purposes. For example, they can be used to prevent a process from running more than once. They can also be used so that control processes (e.g. apache2ctl) know what process to send signals to.

edited Sep 21 '12 at 07:18

answered Sep 21 '12 at 07:12

nneonneo

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so you mean a process has to explicitly create `.pid` file? – thewall Sep 21 '12 at 07:16

Unix .pid file created automatically?

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