Check if a process is running using Python on Linux [duplicate]

Question

I am trying to find if the process is running based on process id. The code is as follows based on one of the post on the forum. I cannot consider process name as there are more than one process running with the same name.

def findProcess( processId ):     ps= subprocess.Popen("ps -ef | grep "+processId, shell=True, stdout=subprocess.PIPE)     output = ps.stdout.read()     ps.stdout.close()     ps.wait()     return output def isProcessRunning( processId):     output = findProcess( processId )     if re.search(processId, output) is None:         return true     else:         return False 

Output :

1111 72312 72311   0   0:00.00 ttys000    0:00.00 /bin/sh -c ps -ef | grep 71676 1111 72314 72312   0   0:00.00 ttys000    0:00.00 grep 71676 

It always return true as it can find the process id in the output string.

Any suggestions? Thanks for any help.

Answer 1

Try:

os.kill(pid, 0) 

Should succeed (and do nothing) if the process exists, or throw an exception (that you can catch) if the process doesn't exist.