I have a simple periodic cron task that must run as root. I want to use Zenity (or similar) to display a GUI informational dialog to user 1000 (or logged in user or all users) when the cron task finishes.
I'm looking for a simple, easy, quick solution. I'll adapt to the requirements of such a simple solution.
Here's where I am so far. My bash script works fine if run manually, but when Anacron runs it, nothing happens and I see
Gtk-WARNING **: cannot open display in the logs. I hoped it would display my dialog to the user after being run by cron.
I realize (after reading related questions) that cron needs to be decoupled from the GUI. If user 1000 is not logged in, I could take one of several options:
- do nothing (possibly acceptable because I want to keep it simple)
- display the dialog with completion message to the user when they log in next time (best)
- display some other type of notification (NOTE: the computer is a desktop system without a mail server installed)
I found these related questions: x11 - Anacron job complains "Gtk-WARNING **: cannot open display" - Unix & Linux Stack Exchange Anacron job complains "Gtk-WARNING **: cannot open display"
shell - How to pass data outside process for zenity progress? - Unix & Linux Stack Exchange How to pass data outside process for zenity progress?
Example Code (from other question which is essentially the same as mine):
#!/bin/bash # Backs up the local filesystem on the external HDD sleep 60 DISPLAY=:0.0 zenity --question --text "Do you want to backup? Be sure to turn on the HDD." if [ $? -ne 0 ] then exit 1 fi *Do backup stuff here*
(zenity:9917): Gtk-WARNING **: cannot open display: run-parts: /etc/cron.daily/backup-on-external exited with return code 1
(I'm running Kubuntu, so a KDE solution would be even better than Zenity, but I already installed Zenity, so I can keep using it.)