Kill & Yank (Cut/Copy and Paste)

Most Emacs commands operate on the region defined by the point, which is the location of the cursor at any given time, and the mark, which is set with the command C-space. To copy or cut a region of text, move the cursor to the start of the text area you are interested in and type C-space. You will see "Mark set" in the echo area. Now move the cursor to the end of the text region (which moves the point) and type M-w for copy or C-w for cut (both called killing text). The text you copy or cut is stored by Emacs in the kill-ring, which is a circular buffer that stores the text snippets you kill in a last-in-first-out order. To paste the most recently stored text, move the cursor to where the text should be inserted, and type C-y. The "y" stands for yank, what you'll see paste referred to in the Emacs help documentation (remember Emacs pre-dated modern windowing systems and other full-screen editors, so the terms cut and paste were not in use yet). After a yank (C-y) command, you can replace the inserted text with earlier kills in turn by typing M-y one or more times. Each time you press M-y the next block of killed text is popped off of the kill ring and inserted into your buffer, replacing the last insert at the same time.

Here are the commands we discussed above, and a few other useful ones:

C-space Set the mark
C-w Cut (kill)
M-w Copy (kill)
C-y Paste (yank)
M-y Paste (yank) next saved selection
C-x h Set point to start of buffer and mark to end of buffer (select the entire buffer)
C-x C-x Go back to the last mark that was set