The defaults system in Mac OS X allows you to manipulate application and system preferences (.plists) from the CLI. In order to display the list of available domains, you can type defaults domains, but the output is all on one line with domains separated by commas (see this previous hint). The following command will translate those commas into newlines, and then paginate the output with more:
defaults domains | tr ',' '\n' | more
This still leaves some lines beginning with spaces, but I haven't yet figured out how to remove those, too.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030424103851644