At some point you would like to be able to take a screenshots on your Raspberry Pidevice. Holding down the shift key and pressing print screen like you do in Windows does not work on your Raspberry Pi. Here is a simple solution, you will need to install a small utility scrot
pi@raspberrypi ~ $sudo apt-get install scrot
Scrot (SCReen shOT) is a simple command line screen capture utility that uses imlib2 to grab and save images. Multiple image formats are supported through imlib2’s dynamic saver modules. Scrot needs to be run from the command prompt, ALT+CTRl+T to open your terminal screen and type in scrot – it will capture what is on your screen. In order to delay the capture like 5-7 seconds so you can clean up your screen and make sure that scrot capture what you really want just add -d 5 switch. This will delay the capture 5 seconds.
In order to capture my screen and delay the capture for 5 seconds
pi@raspberrypi ~ $ scrot -d 5
Scrot is fairly powerful and can do some really cool things so I encourage you look at the manual page to see all the cool things the program can do.