All killed text is recorded in the kill ring, a list of blocks of text that have been killed. There is only one kill ring, used in all buffers, so you can kill text in one buffer and yank it in another buffer. This is the usual way to move text from one file to another. (See Accumulating Text, for some other ways.)
If you have two separate Emacs processes, you cannot use the kill ring to move text. If you are using SXEmacs under X, however, you can use the X selection mechanism to move text from one to another.
If you are using SXEmacs under X and have one Emacs process with multiple frames, they do share the same kill ring. You can kill or copy text in one Emacs frame, then yank it in the other frame belonging to the same process.
The command C-y (
yank) reinserts the text of the most recent
kill. It leaves the cursor at the end of the text and sets the mark at
the beginning of the text. See Mark.
C-u C-y yanks the text, leaves the cursor in front of the text, and sets the mark after it, if the argument is with just a C-u. Any other argument, including C-u and digits, has different results, described below, under “Yanking Earlier Kills”.
To copy a block of text, you can also use M-w
copy-region-as-kill), which copies the region into the kill ring
without removing it from the buffer. M-w is similar to C-w
followed by C-y but does not mark the buffer as “modified” and
does not actually cut anything.