get X11 window id of terminal from shell

Question

How can I get the window ID of the terminal that my shell script is running in?

Background: I need to write a script to do something based on which virtual desktop it is running in. To get the virtual desktop (not current desktop, I may change it while the script is running), I need the window ID of the terminal that the script is running in. If the script is not run from a terminal, it should fail with an error.

Answer 1

I know very little of X11, but running the env command in my terminal, I spotted an environment variable WINDOWID , that shows the same number in different tabs of the same terminal, but a different number in another terminal. Perhaps that's what you need?

It does appear to be an Xterm thing (and probably any terminal that mimicks Xterm s behaviour. The xterm(1) man page only says:

ENVIRONMENT

  Xterm sets several environment variables: ... WINDOWID is set to the X window id number of the xterm window. 

Some other possibly relevant questions with answers:

• https://unix.stackexchange.com/questions/3197/how-to-identify-which-xterm-a-shell-or-process-is-running-in

• Get X window id from process in bash