ls -al | pbcopy #You can then paste the contents of the clipboard using pbpaste:
pbpaste > somefile #This would send the clipboard contents into "somefile". Of course, that's not a great example, as you could have just sent the directory list to the file in the first place (ls -al > somefile). However, it's more useful if you want to paste into a GUI-based application such as Word or BBedit. No more mouse selection required; simply use pbcopy, switch to the GUI app, and hit command-V.
I can't find a 'man' page or help file for either of these commands - anyone know if there are more options available?