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pythonprocessos.systemtaskkill
Yaniv K.
Yaniv K.

Reputation: 286

How to make a program close it's currently running instance upon startup?

I have a command line program which I'd like to keep running until I open it again, so basically a program which first checks if there's currently any already running instance of itself and kill it.

I tried os.system('TASKKILL /F /IM program.exe') but it turned out to be stupid because it also kills itself.

Upvotes: 1

Views: 2406

Answers (4)

Yaniv K.
Yaniv K.

Reputation: 286

Because my working stations don't have access to internet and installing packages is a mess, I ended up coming up with this solution: 

import os

os.system('tasklist > location/tasks.txt')
with open('location/tasks.txt', 'r') as pslist:
    for line in pslist:
        if line.startswith('python.exe'):
            if line.split()[1] != str(os.getpid()):
                os.system(f'TASKKILL /F /PID {line.split()[1]}')
                break
os.remove('location/tasks.txt')

It prints the output of the tasklist command to a file and then checks the file to see if there's a runnig python process with a different PID from it's own.

edit: Figured out I can do it with popen so it's shorter and there are no files involved:

import os

for line in os.popen('tasklist').readlines():
    if line.startswith('python.exe'):
        if line.split()[1] != str(os.getpid()):
            os.system(f'taskkill /F /PID {line.split()[1]}')
            break

Upvotes: 0

David Ferenczy Rogožan
David Ferenczy Rogožan

Reputation: 25451

You can use the psutil library. It simply iterates through all running processes, filter processes with a specific filename and if they have a different PID than the current process, then it kills them. It will also run on any platform, considering you have a right process filename.

import psutil

process_to_kill = "program.exe"

# get PID of the current process
my_pid = os.getpid()

# iterate through all running processes
for p in psutil.process_iter():
    # if it's process we're looking for...
    if p.name() == process_to_kill:
        # and if the process has a different PID than the current process, kill it
        if not p.pid == my_pid:
            p.terminate()

If just the program filename is not unique enough, you may use the method Process.exe() instead which is returning the full path of the process image:

process_to_kill = "c:\some\path\program.exe"

for p in psutil.process_iter():
    if p.exe() == process_to_kill:
         # ...

Upvotes: 3

Lie Ryan
Lie Ryan

Reputation: 64923

The most reliable way to make sure there's only one instance of your application is to create a pid file in a known (fixed) location. This location will usually be in your application data folder or in the temporary directory. At startup, you should check if the pid file exists and if the pid contained there still exists and refers to your target process. If it exists, send a kill signal to it, then overwrite the file with your current pid before starting the rest of the application.

For extra safetiness, you may want to wait until the previous process have completely terminated. This can be done by either waiting/polling to check if the process with that pid still exists, or by polling for the killed process to delete its own pid file. The latter may be necessary if process shutdown are very lengthy and you want to allow the current process to already start working while the old process is shutting down.

Upvotes: 1

Dhnesh Dhingra
Dhnesh Dhingra

Reputation: 301

You can use the process id of already running instance.

import os
os.system("taskkill /pid <ProcessID>")

Upvotes: -1

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