If my memory is correct, the following bash command worked on 10.4.3, but no longer works on 10.4.6:
CODE
$ alias amacs 'open /Volumes/Applications/office/Aquamacs\ Emacs.app'
-bash: alias: amacs: not found
-bash: alias: open /Volumes/Applications/office/Aquamacs\ Emacs.app: not found

Or was I hallucinating?