The TC (tcsh) and Bourne Again (bash) shells have built-in command line editing, and the Korn (ksh) shell can activate this feature. Typically the form of the command line editing is the same as that of the emacs editor. Which means you can go to the beginning of the line, end of the line, forwards or backwards by words, convert to upper-case, convert to lower-case, ...within a command line with just a couple of keystrokes. You also have available a ``kill buffer'', which allows you to copy part of one command line to another command line where it can be ``yanked'' back.