Start a program, take automatic screenshot when its GUI has instantiated, then close program

Question

This is my problem: I have a shell script, where I use gitk --all . for a graphical representation of a git repository. I would like this script to run unattended, and instead of starting gitk in GUI mode where it waits for the user to close it down, I'd like to somehow:

• Start the gitk window
• When it has instantiated its GUI/window, take automatic screenshot of its window
• Once the screenshot has been captured, close gitk

I would imagine, instead of calling

gitk --all .

... in my bash script, I would otherwise call something like this pseudocode:

my_scrshot_cmd --command "gitk --all ." --file myrandomfilename.png

Is this possible to do on Linux - and if so, how can I do it?

Answer 1

You can try to do something like this

gitk --all . &         # You run the gitk and go forward meanwhile
PidOfLastCommand=$!    # You need to remember the PID after
sleep 30s              # Change this value with the needed one... 
import screenshot.png  # From Imagemagick it saves the screenshot
kill $PidOfLastCommand # Let's we kill gitk

echo "### Just DONE ###" 

Notes:

• It requires Imagemagick installed (for import, but you can change the command with the one you prefer).
• You need to wait enough time in sleep ... do some test and take a cosy value (you have to be sure it did its work)