I've tried pgrep = ♥

Wrapping one of the characters in a character class will never exclude anything except the specific unwanted grep line, and is only two extra key presses.

And again, an even better solution is to ensure procps is installed, and use pgrep, which never includes itself in its output and defaults to just the pid; if one needs the extra detail ps provides, ps u $(pgrep cron) will do that.

SpongeBOB wrote:

Thank you all for your reply !

Thank you that have confirmed my thinking. I'm shocked that some people can post "tutorial" without mastering a bit the topic.... Internet peoples..

@boughtonp, oh great indeed I will use also a regex expression in grep to avoid to have the grep itself in the results.

ps aux | grep 'cron$'

Another way to avoid the unwanted expression might be using the syntax grep -v "unwanted_regex_expression". Therefore, you can avoid the grep itself as follows:

ps aux | grep "cron" | grep -v " grep "

The line containing the grep command itself is supposed to be printed at the end due to its higher pid -and then it'll be ignored thanks to the use of the regex 'cron$'-, but who knows...

Thank you all for your reply !

Thank you that have confirmed my thinking. I'm shocked that some people can post "tutorial" without mastering a bit the topic.... Internet peoples..

@boughtonp, oh great indeed I will use also a regex expression in grep to avoid to have the grep itself in the results.

ps aux | grep 'cron$'

Another way to avoid the unwanted expression might be using the syntax grep -v "unwanted_regex_expression". Therefore, you can avoid the grep itself as follows:

ps aux | grep "cron" | grep -v " grep "

Thank you that have confirmed my thinking. I'm shocked that some people can post "tutorial" without mastering a bit the topic.... Internet peoples..

@boughtonp, oh great indeed I will use also a regex expression in grep to avoid to have the grep itself in the results.

ps aux | grep 'cron$'

Another solution is pgrep.

andre@kyoto:~$ ps -aef | grep cron
root      2403     1  0 09:45 ?        00:00:00 /usr/sbin/cron
andre    11016 10606  0 12:45 pts/0    00:00:00 grep --color=auto cron
andre@kyoto:~$ 

The daemon is called cron:

andre@kyoto:~$ ls -l /etc/init.d/cron*
-rwxr-xr-x 1 root root 3059 Oct 11  2019 /etc/init.d/cron
andre@kyoto:~$

Devuan 4, Chimaera, up-to-date.

it's look like that we see the grep process ! not the crond !? Am I right?

Correct (I got the exact same result). Cron is NOT running in your system (you have grepped for 'crond', and therefore in the ps listing it shows the full command-line, which includes 'crond'). If Cron *was* running there would be at least 2 ps lines containing 'crond', one for the daemon & one for grep.

I would like to create a cronjob.

I've found a "tutorial" online -->  https://linuxhandbook.com/crontab/#the-cron-daemon

But it's start already weirdly...

on his example

christopher@pop-os:~$ ps ux | grep crond
christo+  8942  0.0  0.0  18612   840 pts/0    S+   02:16   0:00 grep --color=auto crond

for me it's look like that we see the grep process ! not the crond !? Am I right?

anyway I've tried on my Devuan(Chimaera) and I don't see a crond running.. is that normal ?

Thanks.