Please follow this steps to use mission packs or mods from the command line:
1
Quit Quake.
2
Copy the folder of the mission pack to your "Quake" folder. The "Quake" folder is the folder that holds the "id1" folder.
3
Open the application "Terminal" which is part of the MacOS X installation.
4
Change to the directory that holds the desired Quake application. For example: "cd /Applications/Games/".
5
Start the desired Quake application by appending the command line parameter "-game" followed by the name of your mission pack. For example: "./Quake.app/Contents/MacOS/Quake -game ROGUE".