You can capture screenshots from the command line using the screencapture command. Basically just typing screencapture followed by the path and name of the file to be created will result in a capture of the entire screen. You can also use -c to capture to the clipboard instead of to a file (or Command-Shift-3 if you’re in the GUI). By default screencapture does not get the mouse. You can add the mouse location and pointer to your screenshot using the -C option in your command.
Because you have multiple monitors in many cases you may only want to capture a single monitor. You can specify that using the -m option. If you’re looking to email screen shots (yes, even automatically) you can use the -M option to open a message and paste the screenshot into the message. It would require an osascript to do then send that mail programatically or you could use a screencapture command in an automator workflow.
If you’re using screencapture as an anti-theft or spying on the thief once stolen mechanism of some sort you can use the -x option to suppress the sounds that it will make. Otherwise the thief might get freaked out when they hear a photo sound in the background repeatedly. You can email files created or ftp them to a server if the computer has connectivity using shell scripts.
The binary can also be copied to a jump drive and used for other purposes – which is how I grab the screenshots for the startup sequence and/or the login window of Mac OS X for books.
Overall, the screen shot functionality of Mac OS X is one of the best in the IT industry, partially because so much can be done programatically.
