How to count how many instances of a program are running in the system using python

Question

I would like to know how I can count how many instances of a program are running in the system using python.

For example: if my terminal is open 3 "times", and there are 3 instances of the terminal, how could I count them using python ?

Thanks in advance

Answer 1

This problem is fairly very straightforward if one uses the psutil package in python3

Consider the code snippet below.

import psutil
from collections import Counter

process_ctr = Counter()

for process in psutil.process_iter():
    try:
        process_cmd_list = process.cmdline()
        for p in process_cmd_list:
            process_ctr[p] += 1
    except Exception:
        continue

for pname, cnt in process_ctr.items():
    print(pname, cnt)

Upon running this code, one will get the process name and count printed to stdout

Testing: I opened 3 terminals and I noticed this in the O/P: -bash 3

Sample O/P:

--pdf-renderer 2
--js-flags=--jitless 2
--renderer-client-id=657 1
--launch-time-ticks=75930041264 1
--renderer-client-id=658 1
--launch-time-ticks=76065123981 1
--seatbelt-client=151 4
--renderer-client-id=659 1
--launch-time-ticks=76065777110 1
--renderer-client-id=663 1
--launch-time-ticks=76077686392 1
--renderer-client-id=100 1
--launch-time-ticks=1656826210 1
--renderer-client-id=665 1
--launch-time-ticks=76250675532 1
--seatbelt-client=168 11
--renderer-client-id=666 1
--launch-time-ticks=76252057630 1
-bash 3
/System/Library/PrivateFrameworks/CoreFollowUp.framework/Versions/A/Support/followupd 1
/System/Library/PrivateFrameworks/PhotoAnalysis.framework/Versions/A/Support/photoanalysisd 1
/System/Library/CoreServices/ScopedBookmarkAgent 1
--renderer-client-id=672 1
--launch-time-ticks=76542560240 1
--renderer-client-id=676 1
--launch-time-ticks=76557205901 1

Note:

1. The try, catch is needed as psutil cannot access some process details, as they are owned by the kernel.

Based on user feedback, adding some neat code, just to get the count for the process of interest.

import psutil
from collections import Counter

process_ctr = Counter()

def get_process_count(pname):
    for process in psutil.process_iter():
        try:
            process_cmd_list = process.cmdline()
            for p in process_cmd_list:
                process_ctr[p] += 1
        except Exception:
            continue

    for p, cnt in process_ctr.items():
        if pname in p:
            return cnt

if __name__ == '__main__':
    cnt = get_process_count('qterminal')
    print(f"The cnt is:{cnt}")