Where does the yanked text on commadline get stored?

Question

When you delete characters on the command line using readline commands (e.g. Ctrl-U, you can paste using Ctrl-y, but where does it get stored? It does not seem to use X11 clipboard at all.

Answer 1

It goes into a kill-ring, just like in Emacs. From the GNU Readline docuementation:

When you use a kill command, the text is saved in a kill-ring. Any number of consecutive kills save all of the killed text together, so that when you yank it back, you get it all. The kill ring is not line specific; the text that you killed on a previously typed line is available to be yanked back later, when you are typing another line.

Source: http://www.gnu.org/software/bash/manual/html_node/Readline-Killing-Commands.html

The kill ring is stored in memory allocated via malloc to a char pointer. From kill.c of the readline source:

/* Where to store killed text. */
static char **rl_kill_ring = (char **)NULL;

Answer 2

readline is a library for tty use (at least originally), it is completely oblivious to any graphics environment (thus X clipboard or whatnot).