When Screen Capture command is issued the SystemUIServer runs a program named “screencapture”. This program is located at “/usr/sbin/screencapture”. This utility has various options for taking pictures of the screen.
We can alter the default ScreenCapture File Name and format in Snow Leopard by issuing the following commands in Terminal.
A. To Change default file format to jpg
defaults write com.apple.screencapture type jpg
killall SystemUIServer
B. To Change screen capture file name to the format [current date] at [time]
defaults write com.apple.screencapture name “”
killall SystemUIServer
Instead of empty string a specific name can also be given. In both the cases the second command is uses to restart the screencapture program era only then the changes made will be effective.
Screen Capture Options:
- Pressing cmd+ shift+ 3 will capture the screen to a jpg file (if the default file format is jpg)
- Pressing cmd +ctrl +shift +3 will capture the screen to clipboard
- Pressing cmd+ shift +4 will give a cross-hair. Drag the cross-hair cover the desired area of the screen using left click pressed before releasing the left click will capture to and release to capture a specific area. Pressing ctrl before releasing the mouse will capture to clipboard.
- Pressing cmd+ shift +4 and then the spacebar will turn the cursor to a camera which can be used to capture a specific open window from multiple open windows on the screen.





