Running notify-send via cron

Question

I've written a script, that monitors battery state and shuts down netbook when power is low to prevent hot power off. I've tested the script before running it in cron - everything works as it must: notification pops up, system shuts down. But when I'm trying to run it from cron - everything ok expect notify-send command.
Config scripts:
# crontab -e
# root crontab
# DO NOT EDIT THIS FILE MANUALLY! USE crontab -e INSTEAD
# man 1 crontab for acceptable formats:
# <minute> <hour> <day> <month> <dow> <tags and command>
# <@freq> <tags and command>
DISPLAY=:0.0
SHELL=/bin/bash
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
# SYSTEM DAILY/WEEKLY/... FOLDERS
@hourly ID=sys-hourly /usr/sbin/run-cron /etc/cron.hourly
@daily ID=sys-daily /usr/sbin/run-cron /etc/cron.daily
@weekly ID=sys-weekly /usr/sbin/run-cron /etc/cron.weekly
@monthly ID=sys-monthly /usr/sbin/run-cron /etc/cron.monthly
* * * * * /etc/cron.hourly/powersave
$ cat /etc/cron.hourly/powersave
PasteBin
$ cat /etc/X11/xorg.conf | head -n 6
Section "ServerLayout"
Identifier "X.org Configured"
Screen 0 "Screen0" 0 0
InputDevice "LG_Touchpad" "CorePointer"
InputDevice "LG_Keyboard" "CoreKeyboard"
EndSection
$ echo $DISPLAY
I thought that running one more external script will solve the problem, but it didn't work.
Tried also this command in cron:
* * * * * DISPLAY=:0.0 /etc/cron.hourly/powersave
But also without result.
Anyone found a solution to this problem?

Answer 1

You may also need to have the DBUS_SESSION_BUS_ADDRESS environment variable set.  I have a script that does something like this:
PIDS=$(pgrep urxvtd)
for p in $PIDS; do
dbus=$(grep -z DBUS_SESSION_BUS_ADDRESS /proc/$p/environ | sed 's/DBUS_SESSION_BUS_ADDRESS=//')
user=$(grep -z USER /proc/$p/environ | sed 's/USER=//')
dply=$(grep -z DISPLAY /proc/$p/environ | sed 's/DISPLAY=//')
sudo -u $user sh -c "DBUS_SESSION_BUS_ADDRESS=\"$dbus\" DISPLAY=\"$dply\" /usr/bin/notify-send -i \"$ICON\" \"$TITLE\" \"$BODY\""
done
I chose urxvtd, b/c it's guaranteed to be running... but you can choose another progam.
Last edited by pnutzh4x0r (2011-07-02 02:32:16)