The Raspberry Pi in the kitchen runs relatively stable, but recently the browser (which is showing the openHAB HABpanel) popped up a warning in the upper right corner. That’s annoying, because this area in HABpanel shows the outside temperature.
Before investigating what’s going on, I had to figure out a way to get a screenshot of the display - without running into the kitchen with my mobile phone. And without attaching a keyboard all the time (to press the
The system is running Raspbian. The display manager is LXDE. Raspbian comes with a screenshot tool preinstalled: “scrot”. The nice thing about it: I can take a screenshot from the commandline, while logging in over ‘ssh’.
All I had to do was to teach
scrot where the display is. If you start it without any display settings, it can’t connect to the X Server:
The following environment variables need to be set:
DISPLAY (pointing to the first display, which is
XAUTHORITY (pointing to the
Xauthority file of the currently logged in user):
Both variables need to be exported, which in shell terminology means: any started program can see the environment variable as well. Otherwise it’s just a variable for the shell itself.
After setting the two variables, I can take a screenshot: