Example of using the sleep command

To set an interval before a command is executed:

   (sleep 10; xwd -out zmail.xwd) &

This gives the user 10 seconds to change the appearance of, say, their X window display before the xwd command is executed to save the image of the current window to the file zmail.xwd.

The first command line is run as a background job to allow the user to continue entering commands.