If directory names are given, as output by default, then per-filesystem information is displayed.
The -f option asks the automounter to flush the internal caches. The -m option asks the automounter to provide a list of mounted filesystems, including the number of references to each filesystem and any error which occured while mounting. The -s option asks the automounter to provide system-wide mount statistics.
The -u option asks the automounter to unmount the named filesystems instead of providing information about them. Unmounts are requested, not forced. They merely cause the mounted filesystem to timeout, which will be picked up by amd's main scheduler thus causing the normal timeout action to be taken.
The -v option asks the automounter for its version information. This is a subset of the information output by amd's -v option.
The -M option passes a mount map entry to amd and waits for it to be evaluated, possible causing a mount.