Even on a Windows machine you wouldn't be able to paste using Ctrl + P. (That's the instruction to open the print dialogue box. You need Ctrl + V to paste).
NoM, there is also an app which is on the machine called Grab which will do a screen grab, a partial screen grab or a timed screen grab, or you can highlight the text and do a mouse right click or on the track pad touch with two right hand fingers and one left hand finger to bring up the copy paste menu OR its at the top of the screen in the edit drop down. :)