This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.
To capture the video (filesize: 19MB), using the free "QuickTime Player" application:
In this episode, Jay McGavren shares some of his favorite tricks for working in the shell. No unreadable sed or awk scripts here. Just simple, solid tips you can use every day, including time savers with find, less, ssh, and command-line Ruby.
http://programmer.97things.oreilly.com/wiki/index.php/The_Unix_Tools_Are_Your_Friends