xclip (available as a package for Debian and Ubuntu) enables you to interact with the X clipboard directly from the command-line - without having to use the mouse to cut and paste.

This is particularly useful if you're trying to get command-line output over to an e-mail or web page. Instead of scrolling around in the terminal to cut and paste with the mouse, screen by screen, you can use this:

command --arg | xclip

Then go to whichever graphical program you want to paste the input into, and paste with the middle mouse button or the appropriate menu item.

You can also enter the contents of a file straight into xclip:

xclip /path/to/file

and again, can then paste that directly wherever you want it.

The -o option enables you to operate it the other way around: output the contents of the clipboard straight onto the command line. So, you could, for example, copy a command line from a web page, then use

xclip -o

to output it. To output to a file, use

xclip -o /path/to/file

Use the -selection switch to use the buffer-cut or one of the other selection options, rather than the clipboard default. You can also hook it up to an X display other than the default one (e.g., if you're logged on as a different user on :!) with

xclip -d localhost:1

Article courtesy of Serverwatch