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.