How to get PID by process name?

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

from subprocess import check_outputdef 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_outputdef 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

You can use psutil package:

Install

pip install psutil

Usage:

import psutilprocess_name = "chrome"pid = Nonefor proc in psutil.process_iter():    if process_name in proc.name():       pid = proc.pid

For posix (Linux, BSD, etc... only need /proc directory to be mounted) it's easier to work with os files in /proc.It's 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 a custom exception.)

#!/usr/bin/env pythonimport osimport sysfor 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 bash1487         : -bash 1779         : /bin/bash