How to Determine Pid of Process Started via Os.System

How to determine pid of process started via os.system

os.system return exit code. It does not provide pid of the child process.

Use subprocess module.

import subprocess
import time
argument = '...'
proc = subprocess.Popen(['python', 'bar.py', argument], shell=True)
time.sleep(3) # <-- There's no time.wait, but time.sleep.
pid = proc.pid # <--- access `pid` attribute to get the pid of the child process.

To terminate the process, you can use terminate method or kill. (No need to use external kill program)

proc.terminate()

Terminate Python Process and halt it's underlying os.system command line

You can use taskkill but you have to use the /T (and maybe /F) switch so all child processes of the cmd process are killed too. You get the process id of the cmd task via process.pid.

os.system can start but cannot kill a Python process

Can you use os.kill() instead?

import os
import signal

os.kill(pid, signal.SIGTERM)

If you don't have the pid readily available, use subprocess.check_output to acquire it. (Use subprocess.run instead if you're using Python 3.5+.)

import os
import signal
import subprocess

def get_water_pid():
    return int(subprocess.check_output(['pgrep', '-f', 'water.py']).strip())

def kill_water_process():
    pid = get_water_pid()
    os.kill(pid, signal.SIGTERM)

run os.system command as subprocess python

.split is not doing you any favors here, because you have spaces within quotes that you don't want to split on. Either pass a string directly, and let the shell handle argument separation:

cmd = "/usr/atria/bin/cleartool setview -exec '/usr/bin/python /home/testUser/Development/Scripts/setDoneFlag_Count_Lines.py' testUser__project_5_0_myProject_001"
p=subprocess.Popen(cmd, shell=True)

Or separate the command manually:

cmd = [
    "/usr/atria/bin/cleartool",
    "setview",
    "-exec",
    # single quotes in the argument no longer required, as we're not going through the shell
    "/usr/bin/python /home/testUser/Development/Scripts/setDoneFlag_Count_Lines.py",  
    "testUser__project_5_0_myProject_001"
]
p = subprocess.Popen(cmd)

How to kill a process in window without killing current process

Nice try @Pryanshu

You're doing it right. The problem with your current approach is python and the batch script will be under same process and get's killed at the same time.
So just change the approach a bit

here's the gist:

python

get current process id
while loop 
    read file
    if matches condition
        call kill.bat and pass this python process ID as separate process

batch

get first parameter (which is the python process to kill)
kill the process via taskkill
start the python script as seprate process
exit

Helpers

get current process ID     - pid = os.getpid()
pass id to batch script    - os.system("kill.bat %s" % pid)
batch script get arguments - %1
                             this %1 will contain the first argument passed. 
                             by default %* will contain all the arguments passed to the script.
python start program as 
separate process           - use subprocess python package
cmd start program as 
separate process           - use Start command
kill process via taskkill  - taskkill /F /PID <pid>
                             replace <pid> with your argument

I know you can handle the code part. You'll have to make use of the Helpers and combine them to do the task. Lemme know the output.

If you have any question do comment. I'll try to reply ASAP

Cheers

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