Playing video from one file and audio from another

[i_hate_guis]

How do I simultaneously play video from one file and audio from another using either command line parameters or the ncurses interface (no qt4)? I have searched through all of the help options, and nothing seemed obvious to me (although it probably will seem obvious after I learn how to do it ).

Thank you in advance.

[Rémi Denis-Courmont]

vlc URL_master --input-slave URL_slave