Use Mount to Map a Directory Somewhere

It is sometimes useful to map a directory somewhere else on your disk.  Sometimes symlinks won't do.

One scenario might be a development environment.  Setup a single host in Apache, and then bind your current development directory to that host's location (ie. /var/www/html).

sudo mount -o bind /path/to/be/mounted /place/to/mount

Mount's -o signifies options to follow.  Under the hood, bind remounts one portion of the filesystem's tree structure somewhere else.

You could also use mount options like ro or rw to protect certain actions in certain locations within your FS.