Excluding child processes from ps
- by stefpet
Background: To reload app configuration I need to kill -HUP the parent processes' PIDs. To find PIDs I currently use ps auxf | grep gunicorn with the following example output:
$ ps auxf | grep gunicorn
stpe 4222 0.0 0.2 64524 11668 pts/2 S+ 11:01 0:00 | \_ /usr/bin/python /usr/local/bin/gunicorn app_api:app -c app_api.ini.py
stpe 4225 0.0 0.4 76920 16332 pts/2 S+ 11:01 0:00 | \_ /usr/bin/python /usr/local/bin/gunicorn app_api:app -c app_api.ini.py
stpe 4226 0.0 0.4 76932 16340 pts/2 S+ 11:01 0:00 | \_ /usr/bin/python /usr/local/bin/gunicorn app_api:app -c app_api.ini.py
stpe 4227 0.0 0.4 76940 16344 pts/2 S+ 11:01 0:00 | \_ /usr/bin/python /usr/local/bin/gunicorn app_api:app -c app_api.ini.py
stpe 4228 0.0 0.4 76948 16344 pts/2 S+ 11:01 0:00 | \_ /usr/bin/python /usr/local/bin/gunicorn app_api:app -c app_api.ini.py
stpe 4229 0.0 0.4 76960 16356 pts/2 S+ 11:01 0:00 | \_ /usr/bin/python /usr/local/bin/gunicorn app_api:app -c app_api.ini.py
stpe 4230 0.0 0.4 76972 16368 pts/2 S+ 11:01 0:00 | \_ /usr/bin/python /usr/local/bin/gunicorn app_api:app -c app_api.ini.py
stpe 4231 0.0 0.4 78856 18644 pts/2 S+ 11:01 0:00 | \_ /usr/bin/python /usr/local/bin/gunicorn app_api:app -c app_api.ini.py
stpe 4232 0.0 0.4 76992 16376 pts/2 S+ 11:01 0:00 | \_ /usr/bin/python /usr/local/bin/gunicorn app_api:app -c app_api.ini.py
stpe 5685 0.0 0.0 22076 908 pts/1 S+ 11:50 0:00 | \_ grep --color=auto gunicorn
stpe 5012 0.0 0.2 64512 11656 pts/3 S+ 11:22 0:00 \_ /usr/bin/python /usr/local/bin/gunicorn app_game_api:app -c app_game_api.ini.py
stpe 5021 0.0 0.4 77656 17156 pts/3 S+ 11:22 0:00 \_ /usr/bin/python /usr/local/bin/gunicorn app_game_api:app -c app_game_api.ini.py
stpe 5022 0.0 0.4 77664 17156 pts/3 S+ 11:22 0:00 \_ /usr/bin/python /usr/local/bin/gunicorn app_game_api:app -c app_game_api.ini.py
stpe 5023 0.0 0.4 77672 17164 pts/3 S+ 11:22 0:00 \_ /usr/bin/python /usr/local/bin/gunicorn app_game_api:app -c app_game_api.ini.py
stpe 5024 0.0 0.4 77684 17196 pts/3 S+ 11:22 0:00 \_ /usr/bin/python /usr/local/bin/gunicorn app_game_api:app -c app_game_api.ini.py
stpe 5025 0.0 0.4 77692 17200 pts/3 S+ 11:22 0:00 \_ /usr/bin/python /usr/local/bin/gunicorn app_game_api:app -c app_game_api.ini.py
stpe 5026 0.0 0.4 77700 17208 pts/3 S+ 11:22 0:00 \_ /usr/bin/python /usr/local/bin/gunicorn app_game_api:app -c app_game_api.ini.py
stpe 5027 0.0 0.4 77712 17220 pts/3 S+ 11:22 0:00 \_ /usr/bin/python /usr/local/bin/gunicorn app_game_api:app -c app_game_api.ini.py
stpe 5028 0.0 0.4 77720 17220 pts/3 S+ 11:22 0:00 \_ /usr/bin/python /usr/local/bin/gunicorn app_game_api:app -c app_game_api.ini.py
Based on the above I see that it is 4222 and 5012 I need to HUP.
Question: How can I exclude the child processes and only get the parent process (please note however that the processes I want do also have a parent (e.g. bash) that I'm uninterested with)?
Using a regexp with grep on how much indentation there is in the ascii tree feels dirty. Is there a better way?
Example: The desired output would be something like this.
stpe 4222 0.0 0.2 64524 11668 pts/2 S+ 11:01 0:00 | \_ /usr/bin/python /usr/local/bin/gunicorn app_api:app -c app_api.ini.py
stpe 5012 0.0 0.2 64512 11656 pts/3 S+ 11:22 0:00 \_ /usr/bin/python /usr/local/bin/gunicorn app_game_api:app -c app_game_api.ini.py
This would be easily parseable to be able to automatically find the PIDs in a script that does the HUPing which is the goal.
