How to get PID by process name in Python?

Question

Is there any way I can get the PID by process name in Python?

  PID USER      PR  NI  VIRT  RES  SHR S  %CPU %MEM    TIME+  COMMAND                                                                                        
 3110 meysam    20   0  971m 286m  63m S  14.0  7.9  14:24.50 chrome 

For example I need to get 3110 by chrome.

Answer 1

you can also use pgrep, in prgep you can also give pattern for match

import subprocess
child = subprocess.Popen(['pgrep','program_name'], stdout=subprocess.PIPE, shell=True)
result = child.communicate()[0]

you can also use awk with ps like this

ps aux | awk '/name/{print $2}'

Answer 2

To improve the Padraic's answer: when check_output returns a non-zero code, it raises a CalledProcessError. This happens when the process does not exists or is not running.

What I would do to catch this exception is:

#!/usr/bin/python

from subprocess import check_output, CalledProcessError

def getPIDs(process):
    try:
        pidlist = map(int, check_output(["pidof", process]).split())
    except  CalledProcessError:
        pidlist = []
    print 'list of PIDs = ' + ', '.join(str(e) for e in pidlist)

if __name__ == '__main__':
    getPIDs("chrome")

The output:

$ python pidproc.py
list of PIDS = 31840, 31841, 41942

Answer 3

You can get the pid of processes by name using pidof through subprocess.check_output:

from subprocess import check_output
def get_pid(name):
    return check_output(["pidof",name])


In [5]: get_pid("java")
Out[5]: '23366\n'

check_output(["pidof",name]) will run the command as "pidof process_name", If the return code was non-zero it raises a CalledProcessError.

To handle multiple entries and cast to ints:

from subprocess import check_output
def get_pid(name):
    return map(int,check_output(["pidof",name]).split())

In [21]: get_pid("chrome")

Out[21]: 
[27698, 27678, 27665, 27649, 27540, 27530, 27517, 14884, 14719, 13849, 13708, 7713, 7310, 7291, 7217, 7208, 7204, 7189, 7180, 7175, 7166, 7151, 7138, 7127, 7117, 7114, 7107, 7095, 7091, 7087, 7083, 7073, 7065, 7056, 7048, 7028, 7011, 6997]

Or pas the -s flag to get a single pid:

def get_pid(name):
    return int(check_output(["pidof","-s",name]))

In [25]: get_pid("chrome")
Out[25]: 27698

Answer 4

Complete example based on the excellent @Hackaholic's answer:

def get_process_id(name):
    """Return process ids found by (partial) name or regex.

    >>> get_process_id('kthreadd')
    [2]
    >>> get_process_id('watchdog')
    [10, 11, 16, 21, 26, 31, 36, 41, 46, 51, 56, 61]  # ymmv
    >>> get_process_id('non-existent process')
    []
    """
    child = subprocess.Popen(['pgrep', '-f', name], stdout=subprocess.PIPE, shell=False)
    response = child.communicate()[0]
    return [int(pid) for pid in response.split()]

Answer 5

For posix (Linux, BSD, etc... only need /proc directory to be mounted) it's easier to work with os files in /proc. Its pure python, no need to call shell programs outside.

Works on python 2 and 3 ( The only difference (2to3) is the Exception tree, therefore the "except Exception", which i dislike but kept to maintain compatibility. Also could've created custom exception.)

#!/usr/bin/env python

import os
import sys


for dirname in os.listdir('/proc'):
    if dirname == 'curproc':
        continue

    try:
        with open('/proc/{}/cmdline'.format(dirname), mode='rb') as fd:
            content = fd.read().decode().split('\x00')
    except Exception:
        continue

    for i in sys.argv[1:]:
        if i in content[0]:
            print('{0:<12} : {1}'.format(dirname, ' '.join(content)))

Sample Output (it works like pgrep):

phoemur ~/python $ ./pgrep.py bash
1487         : -bash 
1779         : /bin/bash