Chris Chris - 4 years ago 189
Linux Question

How to find/kill a specific python program

There are two different python programs running in this VM

one is a background job who monitors a folder and then 'does stuff' (with several workers)

10835 ? Sl 0:03 python main.py
10844 ? Sl 34:02 python main.py
10845 ? S 33:43 python main.py


the second one is started via script

20056 pts/1 S+ 0:00 /bin/bash ./exp.sh
20069 pts/1 S+ 0:00 /bin/bash ./exp.sh
20087 pts/1 S+ 0:10 python /home/path/second.py


i have tried numerous things to find a way to kill only the main program (i want to build a cron watchdog), but non succeded

first one i want to find only the hanging 'python main.py' process (accompanied by [defunct]), but i cant even find just this process alone.

the upper ones are from ps -ax (so they both are running currently)
pgrep 'python' returns all PIDs, also from second.py which i dont want: (not usefull, so is pkill therefore)

pgrep 'python'
10835
10844
10845
20087


pgrep 'python main.py' always returns empty, so does pgrep 'main.py;

the only thing which works

ps ax | grep 'python main.py'


but this one also returns its own PID, grepping 'ps' isn't a prefered solution afair. when main.py hangs, it shows "python main.py [defunct]". a

ps ax | grep 'python main.py [defunct]'


is useless as test as it always returns true. pgrep for anything more than 'python' also returns always false. i am a bit clueless.

Answer Source

In your daemon python script you should create PID file:

def writePidFile():
  pid = str(os.getpid())
  f = open('/tmp/my_pid', 'w')
  f.write(pid)
  f.close()

Now killing this process is simple:

kill `cat /tmp/my_pid`

Or you can just use grep and filter its own process:

ps ax | grep 'python main.py [defunct]' | grep -v grep
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