humount man page
humount — remove an HFS volume from the list of known volumes
humount is used to forget about an HFS volume previously mounted with hmount. Either the volume's name or the UNIX path to the volume may be used to specify the volume. If no name or path is given, the current volume is assumed.
It is not strictly necessary to use this command. It does not affect any physical volumes; it only updates the file named .hcwd in the user's home directory used to keep track of the currently known HFS volumes.
Robert Leslie <firstname.lastname@example.org>