I have Firefox 10.6.3 installed on Mac OS X Snow Leopard from the DMG. I can run firefox from the terminal using
/Applications/Firefox.app/Contents/MacOS/firefox-bin. However, if I create a symbolic link:
sudo ln -s /Applications/Firefox.app/Contents/MacOS/firefox-bin /bin/firefox
then it refuses to run, or at least display. When I issue "firefox" from the terminal, I can see the process in top, but never get the GUI to appear.
ls -lr /bin/firefox lrwxr-xr-x 1 root wheel 52 May 5 15:19 /bin/firefox -> /Applications/Firefox.app/Contents/MacOS/firefox-bin