pm2 doesnt work with crontab

mumblebaj

@plainbroke Instead of piping the output to a blackhole, maybe pipe it to a logfile which you can interrogate to see why the pm2 start is not working?

evroom

About /var/log/syslog.
Debian does not use that anymore, already since a while.
As far as I understand it, you will need to get familiar with journalctl.
For cron jobs try this:

$ journalctl --since "1 hour ago" --unit cron.service

$ journalctl -f -u cron.service

Happy hunting.

plainbroke

@evroom,
I get that nothing is found, when I run either of your suggestions.

@mumblebaj
Explain piping, Please…

sdetweil

@plainbroke piping is a technique of stitching together multiple commands to accomplish a task

The vertical bar is called the pipe character
Which takes the output of the left side and presents it as input to the right side , so its like forming a pipe

When I want to find all the MagicMirror processes running in the background I do this

ps -ef

This give the processes and the command line used to start them
But is a lot of data

So I can filter that with grep , and I can pass in data on its stdin

ps -ef | grep -i MagicMirror

That gives just the rows of the process list with MagicMirror on them

But if I want to kill them I need the process id on each row
That’s the second value on each row
I can use the awk command to get that

ps -ef | grep -i MagicMirror | awk ‘{ print $2}’

Now I have the process ids and can issue the kill command with them

ps -ef | grep -i MagicMirror | awk ‘{ print $2}’ |  xargs sudo  kill -9

evroom

@plainbroke said in pm2 doesnt work with crontab:

@evroom,
I get that nothing is found, when I run either of your suggestions.

The journalctl -f shows the current activities.
Simular to tail -f <filename>.
So when there are none, you will see none.
Use that when you know that a cron job is going to occur anytime soon.
The --since "1 hour ago" searches for activities in the last hour.
Change to, for example --since "24 hours ago" for activities in the last 24 hours.
When nothing comes out, then indeed nothing happened (during the time period you are searching in).

Other --since options:

"today"
"00:20"
"2025-11-12"
"2025-11-12 07:30:00"

mumblebaj

@plainbroke Afternoon. What I was saying was that instead of sending your current output to a blackhole, >/dev/null >2&1, i meant sending it to a log file:
30 07 * * 6,0 /usr/local/bin/pm2 start mm >> /home/pi/mon.log 2>&1. This will send the output of the command /usr/local/bin/ pm2 start mm to a log file residing at /home/pi/mof.log. You can then interrogate this log file to see if there were any errors when the command was executed.

So, by pipe I meant redirect the output to somewhere.

plainbroke

@mumblebaj
@sdetweil
@evroom
Thank you all for the information.
I did not get to use it BUT I will save this information, so I do not have to ask again.
I woke up this morning and crontab -e had started my MM like old times… It also shutdown MM last night like it used to…
Tech is great when it does not try to give me a headache, trying to figure it out…

Thanks again guys for all your help.
I think I will close this as solved.
Just Jeff

sdetweil

@plainbroke awesome! Thanks for the feedback