autofs - Format of the automounter maps


DESCRIPTION

       The  automounter maps are files or NIS maps referred to by
       the master map of the  automounter  (see  auto.master(5)).
       The  automounter  maps describe how file systems below the
       mountpoint of the map (given in the auto.master file)  are
       to  be  mounted.   This  describes  the sun map format; if
       another map format is specified (e.g. hesiod), this  docu­
       mentation does not apply.

       Maps  can  be  changed  on the fly and the automouter will
       recognize those changes on the next operation it  performs
       on that map.  This is not true for the auto.master map!


FORMAT

       This  is  a  description  of  the text file format.  Other
       methods of specifying these files may  exist.   All  empty
       lines  or  lines  beginning  with # are ignored. The basic
       format of one line in such maps is:

       key [-options] location

   key
       is the part of the pathname between the mountpoint and the
       path  into  the filesystem mounted.  Usually you can think
       about the key as a subdirectory name below the mountpoint.

   options
       Options  are  optional.   Options can also be given in the
       auto.master file in which case both values are  cumulative
       (this is a difference from SunOS).  The options are a list
       of comma separated options as customary for  the  mount(8)
       command.  There is a special option -fstype= used to spec­
       ify a filesystem type if the  filesystem  is  not  of  the
       default  NFS  type.  This option is processed by the auto­
       mounter and not by the mount command.

   location
       The location specifies from where the file system is to be
       mounted.  In the most cases this will be an NFS volume and
       the usual notation host:pathname is used to  indicate  the
       remote filesystem and path to be mounted.  If the filesys­
       tem to be mounted begins with a  /  (such  as  local  /dev
       entries  or  smbfs  shares) a : needs to be prefixed (e.g.
       :/dev/sda1).


EXAMPLE

         kernel    -ro,soft,intr       ftp.kernel.org:/pub/linux
         boot      -fstype=ext2        :/dev/hda1

         removable -fstype=ext2        :/dev/hdd
         cd        -fstype=iso9660,ro  :/dev/hdc
         floppy    -fstype=auto        :/dev/fd0

       In the first line we have a NFS remote mount of the kernel
       directory  on  ftp.kernel.org.  This is mounted read-only.
       The second line mounts an  ext2  volume  on  a  local  ide
       drive.   The  third  makes a share exported from a Windows
       machine available for automounting.  The  rest  should  be
       fairly self-explanatory.


FEATURES

   Map Key Substitution
       An & character in the location is expanded to the value of
       the key field that matched the line (which  probably  only
       makes sense together with a wildcard key).

   Wildcard Key
       A * in the key field matches all keys.  An example for the
       usefulness is the following entry:

         *         &:/home/&

       This will enable you to access all the home  directory  of
       local  hosts  using  the  path /mountpoint/hostname/local-
       path.

   Variable Substitution
       The following special variables will be substituted in the
       key  and location fields of an automounter map if prefixed
       with $ as customary from shell scripts (Curly  braces  can
       be used to separate the fieldname):

         ARCH           Architecture (uname -m)
         CPU            Processor Type
         HOST           Hostname (uname -n)
         OSNAME         Operating System (uname -s)
         OSREL          Release of OS (uname -r)
         OSVERS         Version of OS (uname -v)

       Additional   entries  can  be  defined  with  the  -Dvari­
       able=Value option to automount(8).

   Executable Maps
       A map can be marked as executable.  The init  script  that
       parses the auto.master map will pass this as a program map
       to the automounter.  A program map will  be  called  as  a
       script  with  the key as an argument.  The script needs to
       return one line of a map or no output at all  if  the  key
       cannot be matched.

       To  do this the automount(8) daemon has to be started with
       the program  type  insted  of  the  file  type.   This  is


       A  executable  map can return an errorcode to indicate the
       failure in addition to no output at all.  All output  sent
       to stderr is logged into the system logs.


UNSUPPORTED

       The  automounter  does  not  support  direct maps or mount
       trees (more than one filesystem to be mounted under a spe­
       cific automount point), and handles SunOS-style replicated
       filesystems only to the extent that mount(8) does.


SEE ALSO

       automount(8), auto.master(5), autofs(8), mount(8).


AUTHOR

       This  manual  page  was  written  by   Christoph   Lameter
       <chris@waterf.org>,   for  the  Debian  GNU/Linux  system.
       Edited by H. Peter Anvin <hpa@transmeta.com>.


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