cron job hdmi on and off

sdetweil

@Sam-0 yes. although you dont need write permission, (except for user)
means anyone else could change the script

evroom

@Sam-0 said in cron job hdmi on and off:

i created two files
off.sh and on.sh
they contain the following lines

wlr-randr --output HDMI-A-1 --off
wlr-randr --output HDMI-A-1 --on

Do you have #!/bin/bash or #!/bin/sh at the very beginning of your shell scripts ?

#! /bin/sh – Execute the file using the Bourne shell, or a compatible shell, assumed to be in the /bin directory
#! /bin/bash – Execute the file using the Bash shell

You can also put /bin/bash in the crontab entry (before /home/username/...).
Then there is no way for cron to not execute it as a shell script and it will even run without the executable bit set.

And what Sam mentioned: the scripts need to be executable but not necessarily writable (chmod 755).
This should normally do the trick.

If you have mail installed (which mail) you can put this at the very beginning of the crontab file:
MAILTO=username (in my case admin).
With
journalctl --since "1 day ago" --unit cron.service --no-pager
you can see if cron ran your script and with mail you can see more details on the cron job executed.

Good luck.

Sam 0

@evroom Thanks for your explanation, I have made adjustments and will check tonight if it works. I will report this back. Thanks for the effort.

Sam 0

unfortunately it still doesn’t work what am I doing

wrong?!

cron info

on sh file

off sh file

error logfile:

evroom

@Sam-0

So it seems that the cronjob is okay.

Can you do:
ˋˋˋls -als /run/user/1000/wayland*ˋˋˋ

I think you need wayland-0 iso wayland-1.

With ˋˋˋ grep username /etc/passwdˋˋˋ (use your username) you can verify that your user has uid 1000.

evroom

@Sam-0

In de laatste 2 regels mist een spatie bij /home.

evroom

This post is deleted!

Sam 0

ok i checked some more and did some tests

when I execute the following I get the error message that I also see in the log

/usr/bin/wlr-randr --output H DMI-A-1 --off
failed to connect to display

also running the sh files via putty gives the error
it seems that the command:
/usr/bin/wlr-randr --output H DMI-A-1 --off
the error message gives the question is this command incorrect or is there an underlying problem?

mumblebaj

@Sam-0 Can you run the following from the command line and she your results:
wlr-randr
ls -als /run/user/1000/wayland*

Share your results. Either the wayland-1 is different as indicated by @evroom or HDMI-A-1 is actually a different version on your system.

Share the results from the above and we take it from there. Also, @evroom has indicated the there is supposed to be a space before /home on the crontab.

Sam 0

@Sam-0 this is the result

checked the cron see below