actually scratch that, do this: cd /Applications/TrueCrypt.app/Contents/MacOS (or whatever the path is for you) ln -s TrueCrypt /usr/local/bin/truecrypt (optional but lets you call truecrypt from other directories) now you can use the truecrypt commands from before probably: truecrypt --restore-headers /path/to/the/usb/device (edit: I think you must type TrueCrypt if you skipped the ln -s step)