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FSTAB(5)										 FSTAB(5)

       fstab - static information about the filesystems

       #include <fstab.h>

       The  file fstab contains descriptive information about the various file systems.  fstab is
       only read by programs, 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.  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  filesystems  of	type ufs, the special file name is the block special file
       name, and not the character special file name.  If a program needs the  character  special
       file  name,  the  program  must create it by appending a ``r'' after the last ``/'' in the
       special file name.

       The second field, fs_file, describes the mount point for the filesystem.  For swap  parti-
       tions, this field should be specified as ``none''.

       The  third  field, fs_vfstype, describes the type of the filesystem.  The system currently
       supports only two types of filesystems:

       ufs	      a local UNIX filesystem

       swap	      a disk partition to be used for swapping

       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 (see fs_type below) plus any additional options appropriate to the filesystem type.

       If the option ``quotas'' is specified, the filesystem is automatically  processed  by  the
       quotacheck(8)  command, and user disk quotas are enabled with quotaon(8).  Filesystem quo-
       tas are maintained in the file named quotas located at the root of the associated filesys-
       tem.   This  restriction  on  the location of the quotas file is needlessly imposed by the
       kernel but may be lifted in the future.	Thus, if the user quota file for /tmp  is  stored
       in /var/quotas/tmp.user, this location can be specified as:


       The  type  of the mount is extracted from the fs_mntops field and stored separately in the
       fs_type field (it is not deleted from the fs_mntops  field).   If  fs_type  is  ``rw''  or
       ``ro''  then  the  filesystem whose name is given in the fs_file field is normally mounted
       read-write or read-only on the specified special file.  If fs_type is ``sw'' then the spe-
       cial  file  is made available as a piece of swap space by the swapon(8) command at the end
       of the system reboot procedure.	The fields other than fs_spec and fs_type are unused.  If
       fs_type	is  specified as ``xx'' the entry is ignored.  This is useful to show disk parti-
       tions which are currently unused.

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

       #define	 FSTAB_RW  "rw" /* read-write device */
       #define	 FSTAB_RO  "ro" /* read-only device */
       #define	 FSTAB_SW  "sw" /* swap device */
       #define	 FSTAB_XX  "xx" /* ignore totally */

       struct fstab {
	    char *fs_spec; /* block special device name */
	    char *fs_file; /* filesystem path prefix */
	    char *fs_vfstype;	/* type of filesystem */
	    char *fs_mntops;	/* comma separated mount options */
	    char *fs_type; /* rw, ro, sw, or xx */
	    int  fs_freq;  /* dump frequency, in days */
	    int  fs_passno;	/* pass number on parallel dump */

       The proper way to read records from fstab  is  to  use  the  routines  getfsent(3),  getf-
       sspec(3), getfstype(3), and getfsfile(3).

       /etc/fstab     The file fstab resides in /etc.


       The fstab file format appeared in 4.0BSD.

4.4 Berkeley Distribution		 January 15, 1996				 FSTAB(5)
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