You can start the Classic Environment from the command line (i.e., the Terminal) by typing:
open -a /System/Library/CoreServices/Classic Startup.appMy default shell in the Terminal is bash, which supports aliases, so I have added the following line to my .profile:
alias classic='open -a /System/Library/CoreServices/Classic\ Startup.app'This way, I can start the Classic environment from the Terminal simply by typing classic.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20011128181853489