One question I often get asked is how to take screenshots on Mac OSX. The answer is really quite simple...
The Everything Shot
To take a screenshot of everything on your display, simply press the "Shift-Command-Number 3" keys, in that order. Your screenshot will be saved to your desktop.
The Windowed Shot
Sometimes you may want to get a screenshot of just a single application. Press the "Shift-Command-Number 4" keys followed by the space bar. You will see your pointer take shap of a camera. Simply click the open application that you want to capture and go grab your screenshot on the desktop.
The Custom Shot
Sometimes you may want to just grab part of a screen or window. To do this, simple repeat with the "Shift-Command-Number 4" keys without the spacebar. You will see your mouse pointer take the shape of an aiming tool with the X and Y coordinates of it's current location. Select a starting point and then click and hold to the area you want to capture. Once selected, simply let go of the clicker and your image will be saved to the desktop.
The Advanced Shot
It is also possible to grab a screenshot from the terminal. Open the terminal and type the following
You can of course name the image anything you want or change the location. The '~/' in the directory simply defines your home folder. Type "screencapture --help" to see the more advanced options available with the screencapture terminal command.