262 lines
7.7 KiB
Groff
262 lines
7.7 KiB
Groff
.\" Copyright (c) 1980, 1989, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)fstab.5 8.1 (Berkeley) 6/5/93
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.\" $FreeBSD$
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.\"
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.Dd June 5, 1993
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.Dt FSTAB 5
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.Os BSD 4
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.Sh NAME
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.Nm fstab
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.Nd static information about the filesystems
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.Sh SYNOPSIS
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.Fd #include <fstab.h>
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.Sh DESCRIPTION
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The file
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.Nm fstab
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contains descriptive information about the various file
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systems.
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.Nm fstab
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is only read by programs, and not written;
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it is the duty of the system administrator to properly create
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and maintain this file.
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Each filesystem is described on a separate line;
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fields on each line are separated by tabs or spaces.
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The order of records in
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.Nm fstab
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is important because
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.Xr fsck 8 ,
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.Xr mount 8 ,
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and
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.Xr umount 8
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sequentially iterate through
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.Nm fstab
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doing their thing.
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.Pp
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The first field,
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.Pq Fa fs_spec ,
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describes the block special device or
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remote filesystem to be mounted.
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For filesystems of type
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.Em ufs ,
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the special file name is the block special file name,
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and not the character special file name.
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If a program needs the character special file name,
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the program must create it by appending a ``r'' after the
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last ``/'' in the special file name.
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.Pp
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The second field,
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.Pq Fa fs_file ,
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describes the mount point for the filesystem.
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For swap partitions, this field should be specified as ``none''.
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.Pp
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The third field,
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.Pq Fa fs_vfstype ,
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describes the type of the filesystem.
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The system can support various filesystem types.
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Only the root, /usr, and /tmp filesystems need be statically
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compiled into the kernel;
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everything else will be automatically loaded at mount
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time. (Exception: the UFS family - FFS, MFS, and LFS cannot
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currently be demand-loaded.) Some people still prefer to statically
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compile other filesystems as well.
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.Bl -tag -width indent -offset indent
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.It Em ufs
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a local
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.Tn UNIX
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filesystem
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.It Em mfs
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a local memory-based
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.Tn UNIX
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filesystem
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.It Em nfs
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a Sun Microsystems compatible ``Network File System''
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.It Em swap
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a disk partition to be used for swapping
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.It Em msdos
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a DOS compatible filesystem
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.It Em cd9660
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a CD-ROM filesystem (as per ISO 9660)
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.\" maybe also say Rock Ridge extensions are handled ?
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.It Em procfs
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a file system for accessing process data
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.It Em kernfs
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a file system for accessing kernel parameter
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.El
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.Pp
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The fourth field,
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.Pq Fa fs_mntops ,
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describes the mount options associated with the filesystem.
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It is formatted as a comma separated list of options.
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It contains at least the type of mount (see
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.Fa fs_type
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below) plus any additional options
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appropriate to the filesystem type. See the options flag
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.Pq Fl o
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in the
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.Xr mount 8
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page and the filesystem specific page, such as
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.Xr mount_nfs 8 ,
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for additional options that may be specified.
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.Pp
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If the options ``userquota'' and/or ``groupquota'' are specified,
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the filesystem is automatically processed by the
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.Xr quotacheck 8
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command, and user and/or group disk quotas are enabled with
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.Xr quotaon 8 .
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By default,
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filesystem quotas are maintained in files named
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.Pa quota.user
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and
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.Pa quota.group
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which are located at the root of the associated filesystem.
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These defaults may be overridden by putting an equal sign
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and an alternative absolute pathname following the quota option.
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Thus, if the user quota file for
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.Pa /tmp
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is stored in
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.Pa /var/quotas/tmp.user ,
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this location can be specified as:
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.Bd -literal -offset indent
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userquota=/var/quotas/tmp.user
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.Ed
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.Pp
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If the option ``noauto'' is specified, the filesystem will not be automatically
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mounted at system startup.
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.Pp
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The type of the mount is extracted from the
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.Fa fs_mntops
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field and stored separately in the
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.Fa fs_type
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field (it is not deleted from the
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.Fa fs_mntops
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field).
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If
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.Fa fs_type
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is ``rw'' or ``ro'' then the filesystem whose name is given in the
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.Fa fs_file
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field is normally mounted read-write or read-only on the
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specified special file.
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If
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.Fa fs_type
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is ``sw'' then the special file is made available as a piece of swap
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space by the
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.Xr swapon 8
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command at the end of the system reboot procedure.
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The fields other than
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.Fa fs_spec
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and
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.Fa fs_type
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are unused.
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If
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.Fa fs_type
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is specified as ``xx'' the entry is ignored.
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This is useful to show disk partitions which are currently unused.
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.Pp
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The fifth field,
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.Pq Fa fs_freq ,
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is used for these filesystems by the
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.Xr dump 8
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command to determine which filesystems need to be dumped.
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If the fifth field is not present, a value of zero is returned and
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.Nm dump
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will assume that the filesystem does not need to be dumped.
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.Pp
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The sixth field,
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.Pq Fa fs_passno ,
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is used by the
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.Xr fsck 8
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program to determine the order in which filesystem checks are done
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at reboot time.
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The root filesystem should be specified with a
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.Fa fs_passno
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of 1, and other filesystems should have a
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.Fa fs_passno
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of 2.
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Filesystems within a drive will be checked sequentially,
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but filesystems on different drives will be checked at the
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same time to utilize parallelism available in the hardware.
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If the sixth field is not present or is zero,
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a value of zero is returned and
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.Xr fsck 8
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will assume that the filesystem does not need to be checked.
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.Bd -literal
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#define FSTAB_RW "rw" /* read/write device */
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#define FSTAB_RQ "rq" /* read/write with quotas */
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#define FSTAB_RO "ro" /* read-only device */
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#define FSTAB_SW "sw" /* swap device */
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#define FSTAB_XX "xx" /* ignore totally */
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struct fstab {
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char *fs_spec; /* block special device name */
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char *fs_file; /* filesystem path prefix */
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char *fs_vfstype; /* File system type, ufs, nfs */
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char *fs_mntops; /* Mount options ala -o */
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char *fs_type; /* FSTAB_* from fs_mntops */
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int fs_freq; /* dump frequency, in days */
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int fs_passno; /* pass number on parallel fsck */
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};
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.Ed
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.Pp
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The proper way to read records from
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.Pa fstab
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is to use the routines
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.Xr getfsent 3 ,
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.Xr getfsspec 3 ,
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.Xr getfstype 3 ,
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and
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.Xr getfsfile 3 .
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.Sh FILES
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.Bl -tag -width /etc/fstab -compact
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.It Pa /etc/fstab
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The file
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.Nm fstab
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resides in
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.Pa /etc .
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.El
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.Sh SEE ALSO
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.Xr getfsent 3 ,
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.Xr getvfsbyname 3 ,
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.Xr dump 8 ,
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.Xr fsck 8 ,
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.Xr mount 8 ,
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.Xr quotacheck 8 ,
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.Xr quotaon 8 ,
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.Xr swapon 8 ,
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.Xr umount 8 .
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.Sh HISTORY
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The
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.Nm
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file format appeared in
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.Bx 4.0 .
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