pm2 doesnt work with crontab

sdetweil

@plainbroke technology is SOOOO much fun! Simple, til it’s not!

Thanks for the feedback. Others will ask, I’m sure they could use your help!

plainbroke

@sdetweil
Ok crontab -e worked last night to shutdown MM. So the pm2 stop all worked.
BUT this morning the pm2 restart mm did nothing.
I used find to get these:

/home/pi/MagicMirror/node_modules/.bin/pm2
/home/pi/MagicMirror/node_modules/pm2
/home/pi/MagicMirror/node_modules/pm2/bin/pm2
/home/pi/MagicMirror/node_modules/pm2/lib/templates/logrotate.d/pm2
/home/pi/MagicMirror/node_modules/pm2/pm2
/usr/local/bin/pm2
/usr/local/lib/node_modules/pm2
/usr/local/lib/node_modules/pm2/bin/pm2
/usr/local/lib/node_modules/pm2/lib/templates/logrotate.d/pm2
/usr/local/lib/node_modules/pm2/pm2

ANY idea on which one would work better.?
Here is my current crontab -e

# Turn off display at 9pm
00 21 * * 0-6 /usr/local/bin/pm2 stop all >/dev/null >2&1
# Turn on screen Monday - Friday at 6:45 am
45 06 * * 1-5 /usr/local/bin/pm2 start mm >/dev/null >2&1
# Turn on screen Saturday - Sunday at 7:30 am
30 07 * * 6,0 /usr/local/bin/pm2 start mm >/dev/null >2&1

sdetweil

@plainbroke which one, if any , are in the path
Are they all executable?

ls -laF
Will give you the permissions mask

Are any of them links to another?

What changed?

/usr/local/bin/pm2
Should be the one

sdetweil

@plainbroke also look in /var/log/syslog
To find the logging of the execute at the time it should fire

plainbroke

@sdetweil
Weird, I do not have /var/log/syslog.
Even did a find for it nothing, popped up…

pi@Pixie:~ $ ls -laF
total 348
drwx------ 15 pi   pi     4096 Nov 10 15:36 ./
drwxr-xr-x  3 root root   4096 Sep 30 19:18 ../
-rw-------  1 pi   pi     9080 Nov 10 13:17 .bash_history
-rw-r--r--  1 pi   pi      220 Sep 30 19:06 .bash_logout
-rw-r--r--  1 pi   pi     3523 Sep 30 19:06 .bashrc
drwx------ 13 pi   pi     4096 Nov  7 18:22 .cache/
drwx------ 22 pi   pi     4096 Nov  8 12:57 .config/
drwx------  3 pi   pi     4096 Nov  7 17:49 .dbus/
drwxrwxr-x  2 pi   pi     4096 Sep 30 19:17 Desktop/
drwx------  2 pi   pi     4096 Nov  7 23:11 Documents/
-rw-rw-r--  1 pi   pi        0 Nov  7 20:00 .gitconfig
-rw-rw-r--  1 pi   pi       81 Nov  7 18:24 .gtkrc-2.0
-rw-rw-r--  1 pi   pi   222126 Oct 27 18:52 install.log
drwx------  4 pi   pi     4096 Sep 30 19:18 .local/
drwxrwxr-x 16 pi   pi     4096 Nov  8 12:54 MagicMirror/
-rwxrwxrwx  1 pi   pi      320 Jun 12  2022 mm.json*
-rwxrwxrwx  1 pi   pi       38 Jul 16  2023 mm.sh*
drwx------  4 pi   pi     4096 Nov  6 21:05 .mozilla/
drwxrwxr-x  4 pi   pi     4096 Oct 27 18:30 .npm/
drwx------  3 pi   pi     4096 Oct 27 18:52 .pki/
drwxrwxr-x  5 pi   pi     4096 Nov  9 17:24 .pm2/
-rw-r--r--  1 pi   pi      807 Sep 30 19:06 .profile
-rw-rw-r--  1 pi   pi       66 Oct 27 19:22 .selected_editor
drwxrwxr-x  4 pi   pi     4096 Nov 10 15:43 shared/
-rw-r--r--  1 pi   pi        0 Sep 30 19:18 .sudo_as_admin_successful
drwx------  3 pi   pi     4096 Nov  5 17:30 .vnc/
-rw-------  1 pi   pi       50 Nov  9 17:24 .Xauthority
-rw-------  1 pi   pi     8238 Nov  9 19:32 .xsession-errors
-rw-------  1 pi   pi     7945 Nov  9 17:24 .xsession-errors.old

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"