I want to check 10+ local Git repositories if they have any unpushed commit, before shutdown.

(I always forgot to push them, so later, the next morning I came office and back home again)

I think maybe the shutdown process can check some conditions to meet, if any condition is not met, then give the user the choice to continue to shutdown or just cancel.

Then, I can write something to hook the shutdown to check my Git repository to push.

EDIT

I have changed the title from Ubuntu shutdown hook to Compiz shutdown hook. I want to hook to the small lovely shutdown button, rather then click another ugly shortcut icon on the desktop.