"shawn bright" <[email protected]> wrote
So, my question is, how can i write something that will know if there
is an instance of that something already running?
I am doing this in python 2.5 on Ubuntu, if that matters ( which i
suspect it does ).
I suspect the simplest way is to use the ps command and grep.
Wrap your code in a shell script that checks ps before launching
the script.
If thats not acceptable call ps from subprocess module as soon
as you start, hopefuilly that won;t break anything although the
processes will be running together briefly.
If so you could do the check then fork() or exec() to create the
real new process...
Finally you can write a signal file into /tmp and then look for that
file on startup. Don't forget to delete it when you exit though!
Lots of options depending on how hard core you need to be!
HTH,
--
Alan Gauld
Author of the Learn to Program web site
http://www.alan-g.me.uk/
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