The text-only design vastly reduces the resources needed to run the program, making it a strong choice for very light computers as well as systems where a graphical environment (such as the X Window System) is not available. By eliminating the use of mouse, the program performs a wide array of tasks faster than its mouse-driven counterparts, albeit after some practice with the non-mouse paradigm.
Owing to the console-orientation and portability goals of the project, cmus is controlled exclusively via the keyboard (excepting the operation through cmus-remote). Commands are loosely modeled after those of the vi text editor. General operation mimics being in command-mode of vi, where complex commands are issued by prepending them with a colon, (e.g. ":add /home/user/music-dir"), simpler, more common commands are bound to individual keys, such as "j/k" moving down/up, or "x" starting playback, and searches beginning with "/" as in "/the beatles" searching (case insensitive) for any tracks containing both "the" and "beatles," order irrelevant. Note that default case insensitivity and searching for each of the space-separated terms is a deviation from the Regular Expressions engine that vi uses.
Any command may be bound to a single key, expediting complex commands' repeated use. The default configuration is fully customizable, which is a boon to non-English keyboard layouts.
A small tool called 'cmus-remote' allows manipulation of any aspect of cmus available in the interactive program from externally.