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FSTAB(5)                   Linux Programmer's Manual                  FSTAB(5)



NAME
       fstab - static information about the filesystems

SYNOPSIS
       #include <fstab.h>

DESCRIPTION
       The  file  fstab  contains  descriptive information about the various file systems.  fstab is only read by pro-
       grams, and not written; it is the duty of the system administrator to properly create and maintain  this  file.
       Each  filesystem  is  described on a separate line; fields on each line are separated by tabs or spaces.  Lines
       starting with '#' are comments. blank lines are ignored.  The order of records in fstab  is  important  because
       fsck(8), mount(8), and umount(8) sequentially iterate through fstab doing their thing.

       The first field, (fs_spec), describes the block special device or remote filesystem to be mounted.

       For  ordinary  mounts  it  will  hold  (a link to) a block special device node (as created by mknod(8)) for the
       device to be mounted, like '/dev/cdrom' or '/dev/sdb7'.  For NFS  mounts  one  will  have  <host>:<dir>,  e.g.,
       'knuth.aeb.nl:/'.  For procfs, use 'proc'.

       Instead of giving the device explicitly, one may indicate the (ext2 or xfs) filesystem that is to be mounted by
       its UUID or volume label (cf.   e2label(8)  or  xfs_admin(8)),  writing  LABEL=<label>  or  UUID=<uuid>,  e.g.,
       'LABEL=Boot'  or 'UUID=3e6be9de-8139-11d1-9106-a43f08d823a6'.  This will make the system more robust: adding or
       removing a SCSI disk changes the disk device name but not the filesystem volume label.

       The second field, (fs_file), describes the mount point for the filesystem.  For  swap  partitions,  this  field
       should be specified as 'none'. If the name of the mount point contains spaces these can be escaped as '\040'.

       The  third field, (fs_vfstype), describes the type of the filesystem.  Linux supports lots of filesystem types,
       such as adfs, affs, autofs, coda, coherent, cramfs, devpts, efs, ext2, ext3, hfs, hpfs,  iso9660,  jfs,  minix,
       msdos,  ncpfs,  nfs, ntfs, proc, qnx4, reiserfs, romfs, smbfs, sysv, tmpfs, udf, ufs, umsdos, vfat, xenix, xfs,
       and possibly others. For more details, see mount(8).  For the filesystems currently supported  by  the  running
       kernel,  see  /proc/filesystems.   An  entry  swap  denotes  a  file  or partition to be used for swapping, cf.
       swapon(8).  An entry ignore causes the line to be ignored.  This is useful to show disk  partitions  which  are
       currently unused.  An entry none is useful for bind or move mounts.

       mount(8)  and  umount(8) support filesystem subtypes. The subtype is defined by '.subtype' suffix.  For example
       'fuse.sshfs'. It's recommended to use subtype notation rather than add any prefix to the first fstab field (for
       example 'sshfs#example.com' is depreacated).

       The fourth field, (fs_mntops), describes the mount options associated with the filesystem.

       It  is  formatted  as a comma separated list of options.  It contains at least the type of mount plus any addi-
       tional options appropriate to the filesystem type.  For documentation on the available options for non-nfs file
       systems,  see  mount(8).   For documentation on all nfs-specific options have a look at nfs(5).  Common for all
       types of file system are the options ''noauto'' (do not mount when "mount -a" is given, e.g.,  at  boot  time),
       ''user''  (allow  a user to mount), and ''owner'' (allow device owner to mount), and ''comment'' (e.g., for use
       by fstab-maintaining programs).  The ''owner'' and ''comment'' options are Linux-specific.  For  more  details,
       see mount(8).

       The fifth field, (fs_freq), is used for these filesystems by the dump(8) command to determine which filesystems
       need to be dumped.  If the fifth field is not present, a value of zero is returned and dump  will  assume  that
       the filesystem does not need to be dumped.

       The  sixth field, (fs_passno), is used by the fsck(8) program to determine the order in which filesystem checks
       are done at reboot time.  The root filesystem should be specified with a fs_passno of 1, and other  filesystems
       should have a fs_passno of 2.  Filesystems within a drive will be checked sequentially, but filesystems on dif-
       ferent drives will be checked at the same time to utilize parallelism available in the hardware.  If the  sixth
       field  is  not  present  or zero, a value of zero is returned and fsck will assume that the filesystem does not
       need to be checked.

       The proper way to read records from fstab is to use the routines getmntent(3).

FILES
       /etc/fstab

SEE ALSO
       getmntent(3), mount(8), swapon(8), fs(5), nfs(5)

HISTORY
       The ancestor of this fstab file format appeared in 4.0BSD.

AVAILABILITY
       This  man  page   is   part   of   the   util-linux-ng   package   and   is   available   from   ftp://ftp.ker-
       nel.org/pub/linux/utils/util-linux-ng/.



Linux 2.2                        15 June 1999                         FSTAB(5)