There are two(2) automounter implementations available for Linux: one based on the Berkeley automounter daemon (amd), and one based on the Solaris automounter (automount).   Both are configured in a similar manner: Both are given mount points.

  amd mount points and map files are often defined on the command line:

   amd -a /amd /mnt/wren /etc/nfs/wren.map

/amd 

   is the real physical mounts are made

/mnt/wren 

   the mount point for the user directory or folder, like any NFS mount points, this directory must already exist

/etc/nfs/wren.map 

   The map file that defines the filesystem that is mounted on /mnt/wren is named /etc/nfs/wren.map 

for automount, the mount points are usually not defined on the automount command line.   Instead, automount mount points are defined in the auto.master file, which lists all of the maps that are used to define the automatically mounted filesystems.   The format of entries in the auto.master file is

  mount-point   map-name   options

  The options are standard mount command options.   Generally, they are not defined here.   Most auto.master entries contain only a mount point and a map file.

  To reproduce the amd configuration shown previously, the auto.master file would contain

   /mnt/wren   /etc/nfs/wren.map

  On Red Hat systems, the automount daemon is started by the /etc/rc.d/init.d/autofs script.   run autofs reload to load automounter after you change the file.

  The map file contains the information needed to mount the correct NFS filesystem.   The format of a map file entry is

   key   options   filesystem

key is a subdirectory name.   when anyone accesses this subdirectory, the filesystem is mounted options are the standard mount command options filesystem is the pathname of the filesystem being mounted.

  example: 

      doc    -ro   wren:/usr/local/doc

      man    -ro   wren:/usr/local/man