.\" Copyright (c) 1980, 1989 The Regents of the University of California.
.\" %sccs.include.redist.man%
.\" @(#)fstab.5 6.4 (Berkeley) %G%
fstab \- static information about the filesystems
contains descriptive information about the various file
is only read by programs, and not written;
it is the duty of the system administrator to properly create
Each filesystem is described on a separate line;
fields on each line are separated by tabs or spaces.
sequentially iterate through
describes the block special device or
remote filesystem to be mounted.
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.
describes the mount point for the filesystem.
For swap partitions, this field should be specified as ``none''.
describes the type of the filesystem.
The system currently supports four types of filesystems:
a local memory-based UNIX filesystem
a Sun Microsystems compatible ``Network File System''
a disk partition to be used for swapping
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
below) plus any additional options
appropriate to the filesystem type.
If the options ``userquota'' and/or ``groupquota'' are specified,
the filesystem is automatically processed by the
command, and user and/or group disk quotas are enabled with
filesystem quotas are maintained in files named
which are located at the root of the associated filesystem.
These defaults may be overridden by putting an equal sign
and an alternative absolute pathname following the quota option.
Thus, if the user quota file for /tmp is stored in /var/quotas/tmp.user,
this location can be specified as:
userquota=/var/quotas/tmp.user
The type of the mount is extracted from the
field and stored separately in the
field (it is not deleted from the
is ``rw'' or ``ro'' then the filesystem whose name is given in the
field is normally mounted read-write or read-only on the
is ``sw'' then the special file is made available as a piece of swap
command at the end of the system reboot procedure.
is specified as ``xx'' the entry is ignored.
This is useful to show disk partitions which are currently unused.
is used for these filesystems by the
command to determine which filesystems need to be dumped.
If the fifth field is not present, a value of zero is returned and
will assume that the filesystem does not need to be dumped.
program to determine the order in which filesystem checks are done
The root filesystem should be specified with a
of 1, and other filesystems should have a
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
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 */
.ta \w'#define 'u +\w'char\ \ 'u +\w'*fs_vfstype;\ \ 'u
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
is to use the routines getfsent(), getfsspec(), getfstype(),