Using GrabGrab is a utility that lets you take pictures of what is visible on your monitor, called screen shots. This book is filled with thousands of screen shots. If you’re a teacher, it’s great to include screen shots in your handouts. If you’re having trouble with something, you can send a screen shot to your favorite tech support person so they have a clearer idea of the problem. You can even use the Grab service to take a quick screen shot and drop it into an email or a TextEdit document.
To use Grab:
- Double-click the Grab icon to open it.
- To capture the entire screen, press Command Z.
To capture a selected portion of the screen, press Command Shift A. You’ll get a pointer as shown below; press-and-drag to select the area you want to capture.

This is what the pointer looks like as you
start to grab a portion of the screen.

When you let go, the new file will open
instantly in Grab, waiting for you to save it.
With the Command-Shift-A procedure above, you cannot grab the pointer nor can you grab active windows – the windows are always in the background. You can’t get pop-up menus, either. So to get one of these items, press Command Shift Z; you’ll get the message shown below, the “Timed Screen Grab.” Hit Return to activate it, then go to the window, pop-up menu, dialog box, etc., that you want a screen shot of, put everything in position, and hold it until the timer goes off. The screen shot will open instantly in Grab.

And how is this better than Cmd-Shift 3 and Cmd-Shift 4? I guess the improvement is the ability to capture the active/current Window, like an Alt-PrtScr on Windows.
On Windoze I use SnagIt, it can capture any widget in a window, record movies of you using your computer, etc. Is there a Mac equivalent for more advanced capture features?
I also use snapndrag http://www.yellowmug.com/snapndrag/
Also http://shinywhitebox.com/home/home.html allows ofr video capture of your screen
Both great apps for this purpose