Do you ever wish you could cut two or more separate pieces of text
at once from a window?  Do you ever need to save the output from one
command for reuse in several subsequent tasks?  Do you ever find
yourself wanting some easy means of globally exporting data, e.g.
to a parent shell, to another xterm or application, or to another
machine or user?  If you answer yes to any of these questions, then
xcb is for you.

Xcb provides access to the cut buffers built into every X server.
It allows the buffers to be manipulated either via the command line,
or with the mouse in a point and click manner.  The buffers can be
used as holding pens to store and retrieve arbitrary data fragments,
so any number of different pieces of data can be saved and recalled later.
The program is designed primarily for use with textual data.

WWW: http://oldhome.schmorp.de/marc/xcb.html