With no arguments,
displays the name and path to the "current" HFS volume as well as the names
and paths of all previously mounted ("known") volumes.
With an argument,
changes the current volume to be the one specified. Either the name of the
volume or the path to its UNIX source can be specified. The volume must have
been previously mounted using
R hmount .
A separate "current working directory" is maintained for each mounted volume.
This information is kept in a file named
in the user's home directory.