Given PID, make sure a process is running on Unix?

[Thomas Jensen]

VanL wrote:
> Hello,
> 
> I am trying to get write a python script that  on Unix reads a PID from 
> a file and, if that process is still running, exits.  If the process is 
> not running, the process would be started.
> 
> I have everything written except the part that makes sure the process is 
> running.  I have poked through the os module, but I can only seem to 
> find information about the current process or child processes, not just 
> some arbitrary process.

If your system has a 'proc' device, you could do something like this:
     os.path.isdir('/proc/%d' % pid)
Most Unix flavours have a proc device AFAIK.

-- 
Best Regards
Thomas Jensen
(remove underscore in email address to mail me)