5

I build a cronjob to download a new picture from a source every ten minutes and set it as wallpaper using feh. The file is downloaded but the wallpaper doesn't change. Where is the problem? crontab -e executes commands as the user so it should be as i would run the line - which works btw.

here is the script

#!/bin/sh

#Filename
file="space-"$(date +%x_%H:%M:%S)

#save it 
wget http://rammb.cira.colostate.edu/ramsdis/online/images/latest_hi_res/himawari-8/full_disk_ahi_true_color.jpg -O /home/tim/Bilder/Wallpaper/$file -o /dev/null

#set background
feh --bg-max /home/tim/Bilder/Wallpaper/$file

Here's crontab -e for the user which background should be changed (aka me)

*/10 * * * * /bin/sh /home/tim/Dokumente/Scripts/wallpaper.sh

In my syslog I found these lines

Jan 31 21:40:01 LinuxMint CRON[18209]: (tim) CMD (/bin/sh /home/tim/Dokumente/Scripts/wallpaper.sh)
Jan 31 21:40:11 LinuxMint CRON[18204]: (CRON) info (No MTA installed, discarding output) 
7

Unfortunately, it's not emphasized enough that the environment processes started by cron get is very simple, it contains only the most vital variables and values. You can check it by running a shell script that contains only

#!/bin/bash

set > /tmp/myset.txt

You will see that there is no DISPLAY variable set there that would be needed to run any X-based applications (and apart from rare exceptions, all we use is that kind).

You have to put something like

export DISPLAY=:0.0

into your script and to have better odds.

5

To complete Gombai's answer with instructions:

Run env | grep -i display and check the value of DISPLAY. It is probably :0.0, or :0.

Modify your crontab accordingly:

*/10 * * * * DISPLAY=:0 /bin/sh /home/tim/Dokumente/Scripts/wallpaper.sh
1
  • Your solution helped me a lot, finally I get my script running! Keep up the good work! Oct 12 at 19:02

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