Networking Guide
Chapter 13, Configuring the NFS automounter

Master automount maps

Master automount maps

A master map provides:

By default, automount looks for an NIS master map named auto.master when it starts up. Options to the automount command can direct automount to use a local master map (-f option) or ignore the NIS master map (-m option). If a local master map is specified with the -f option and the -m option is not specified, automount reads both master maps, but entries in the local master map have priority if duplicates between the two master maps occur. The names of direct, indirect, and built-in maps can be passed as arguments to the automount command in lieu of or in addition to using a master map.

Each line in the master map (by convention called /etc/auto.master) has the syntax:

mount_point map_name [ mount_options ]

mount_point
May be either a full pathname or the string ``/-''. A full pathname tells automount that the map-name field value is the name of an indirect map or a built-in map. Whether an indirect or built-in map is used, automount uses the pathname to build the mount point on which automount is to mount the filesystems listed in the map. If any of the directories in the pathname do not exist, automount creates them, if possible. If the basename directory exists and is not empty, mounting on it hides its contents. automount issues a warning message in this case. The string ``/-'' tells automount that the map-name field value is the name of a direct map that automount is to read for filesystems to mount.

map_name
Is the name of a direct, indirect, or built-in map.

mount_options
Is an optional list of options (separated by commas) that regulate the mounting of the entries mentioned in map_name, unless the entries in map_name list other options. Mount options listed in a direct or indirect map override options listed here. You may specify options here that are defined for NFS-type mounts in the mount(ADM) reference manual page, excluding bg (background) and fg (foreground), which do not apply.
For a sample map, see ``Creating master automount maps''.