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+--- Thread: how to get PID's of linux commands executed through python modules? (/thread-24933.html)
how to get PID's of linux commands executed through python modules? - Manikandan_PS - Mar-11-2020
1]i am using python 2.6.6
2]i need to execute a linux command { tail -f file1 -f file2 | egrep --line-buffered "string1|string2" > tofile.txt &} in background.
3]when executing the command on a linux shell, i could see the pid's as "[1] 2740 2741" but, i am not able to read this output through subprocess.Popen, os.popen and commands.getstatusoutput. commands give error as "syntax error near unexpected token '&' and others give empty string as output and command is running the background successfully though.
4]subprocess.Popen gives a pid but when killed or terminated i could still see the tail and egrep pid's staying alive.
5]how to kill/terminate all these processes ?
how to get PID's of linux commands executed through python modules? - Manikandan_PS - Mar-12-2020
1]i am using python 2.6.6
2]i need to execute a linux command { tail -f file1 -f file2 | egrep --line-buffered "string1|string2" > tofile.txt &} in background.
3]when executing the command on a linux shell, i could see the pid's as "[1] 2740 2741" but, i am not able to read this output through subprocess.Popen, os.popen and commands.getstatusoutput. commands give error as "syntax error near unexpected token '&' and others give empty string as output and command is running the background successfully though.
4]subprocess.Popen gives a pid but when killed or terminated i could still see the tail and egrep pid's staying alive.
5]how to kill/terminate all these processes ?
RE: how to get PID's of linux commands executed through python modules? - buran - Mar-12-2020
Please, don't start new threads. Just bump your original thread after reasonable amount of time. Excessive/frequent bumping is not tolerated.
RE: how to get PID's of linux commands executed through python modules? - buran - Mar-12-2020
(Mar-12-2020, 07:03 AM)Manikandan_PS Wrote: i am not able to read this output through subprocess.Popen, os.popen and commands.getstatusoutput. commands give error as "syntax error near unexpected token '&' and others give empty string as output and command is running the background successfully though.Maybe show your code...
(Mar-12-2020, 07:03 AM)Manikandan_PS Wrote: subprocess.Popen gives a pid but when killed or terminated i could still see the tail and egrep pid's staying alive.Do you pass
shell=True? in which case as docs state:Quote:Note that if you set the shell argument to True, this is the process ID of the spawned shell.
RE: how to get PID's of linux commands executed through python modules? - Manikandan_PS - Mar-12-2020
understood...thought of moving the question to the appropriate group and surely not to repeat the question again.
yes i passed shell=True and i get 3 consecutive PID's, 1 for shell and the others for tail and egrep as seen through command "ps -ae" but, when shell pid is killed the other two still remains.
i am just trying these commands over python shell to see the behavior and then finally to use it in my script:
###############from python shell environment############
import os
import subprocess
command_1 = "tail -f file1*.log -f file2* -f file3* | egrep --line-buffered "string1:|string2" > /export/home/output.txt &"
p = subprocess.Popen(command_1,stdin=subprocess.PIPE,stdout=subprocess.PIPE,shell=True)
(out,error) = p.communicate()
###############from python shell environment############
1] p.pid says 22559 and 22560 for tail and 22561 for egrep as seen through linux command <ps -ae>
2] upon calling p.terminate(), i don't see pid 22559 but the other pid's 22560 and 22561 still remains. how to terminate all these pids ?
(Mar-12-2020, 07:16 AM)Manikandan_PS Wrote: understood...thought of moving the question to the appropriate group and surely not to repeat the question again.both out and error were returning empty but when i execute this command on a linux shell environment i get the pids for both tail and egrep. how to get these two pid's in python ?
yes i passed shell=True and i get 3 consecutive PID's, 1 for shell and the others for tail and egrep as seen through command "ps -ae" but, when shell pid is killed the other two still remains.
i am just trying these commands over python shell to see the behavior and then finally to use it in my script:
###############from python shell environment############
import os
import subprocess
command_1 = "tail -f file1*.log -f file2* -f file3* | egrep --line-buffered "string1:|string2" > /export/home/output.txt &"
p = subprocess.Popen(command_1,stdin=subprocess.PIPE,stdout=subprocess.PIPE,shell=True)
(out,error) = p.communicate()
###############from python shell environment############
1] p.pid says 22559 and 22560 for tail and 22561 for egrep as seen through linux command <ps -ae>
2] upon calling p.terminate(), i don't see pid 22559 but the other pid's 22560 and 22561 still remains. how to terminate all these pids ?