"What does X do in LINUX" is a very vague question.
Hotkey combinations like this can sometimes be global, but they can also be specific to some application. And they are also generally user configurable.
linuxzilla.com's answer above is likely the default answer for some common Linux environments, but it doesn't cover every possible situation. At the very least you should say what distribution and the desktop environment you're using, and/or what programs, so that you're most likely to get an answer appropriate for you.