How do I take a screenshot on a Mac? Possible Duplicate:
  How do I take a screenshot on my Mac?  




I haven't found any shortcut or application on my Mac which provide such functionality.

I would like to know the keyboard shortcut.
Command ⌘-Shift ⇧-3 will save a screenshot of the whole screen to your desktop. Command ⌘-Control ⌃-Shift ⇧-3 copies it to your clipboard.
⌘-⇧-4 lets you drag to take a shot of a portion of the screen, or press Space to select a specific window. Add Control ⌃ to the mix to copy to to the clipboard.


You can view and change these in the Keyboard pane of System Preferences, under the Keyboard Shortcuts tab: