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Pgrep for processes which are not associated with a terminal in Ubuntu

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# 1  
Old 12-11-2016
Pgrep for processes which are not associated with a terminal in Ubuntu
I would like to find all of the PIDs of processes which are not associated with a terminal and started by CRON.

When I do the ps aux | less command, I see in the TTY field a lot of processes with ? character

I would like to get those processes ID, is there a way to do that with pgrep?

I tried looking at the documentation but it's not very clear...
# 2  
Old 12-11-2016
CRON jobs are never associated with a terminal, but there are processes without a terminal that are not CRON jobs.
Find the PID of the "cron" daemon
Code:
pgrep -o -x -u 0 cron

Now find the PIDs of its children
Code:
pgrep -P <pid_of_cron_daemon>

All in one
Code:
pgrep -P `pgrep -ox cron`

Last edited by MadeInGermany; 12-11-2016 at 06:28 AM.. Reason: added -u 0
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