1.\" Copyright (c) 1980, 1989, 1991 The Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" from: @(#)fstab.5 6.5 (Berkeley) 5/10/91 33.\" $Id: fstab.5,v 1.3 1993/11/28 08:48:42 mycroft Exp $ 34.\" 35.Dd May 10, 1991 36.Dt FSTAB 5 37.Os BSD 4 38.Sh NAME 39.Nm fstab 40.Nd static information about the filesystems 41.Sh SYNOPSIS 42.Fd #include <fstab.h> 43.Sh DESCRIPTION 44The file 45.Nm fstab 46contains descriptive information about the various file 47systems. 48.Nm fstab 49is only read by programs, and not written; 50it is the duty of the system administrator to properly create 51and maintain this file. 52Each filesystem is described on a separate line; 53fields on each line are separated by tabs or spaces. 54The order of records in 55.Nm fstab 56is important because 57.Xr fsck 8 , 58.Xr mount 8 , 59and 60.Xr umount 8 61sequentially iterate through 62.Nm fstab 63doing their thing. 64.Pp 65The first field, 66.Pq Fa fs_spec , 67describes the block special device or 68remote filesystem to be mounted. 69For filesystems of type 70.Em ufs , 71the special file name is the block special file name, 72and not the character special file name. 73If a program needs the character special file name, 74the program must create it by appending a ``r'' after the 75last ``/'' in the special file name. 76.Pp 77The second field, 78.Pq Fa fs_file , 79describes the mount point for the filesystem. 80For swap partitions, this field should be specified as ``none''. 81.Pp 82The third field, 83.Pq Fa fs_vfstype , 84describes the type of the filesystem. 85The system currently supports nine types of filesystems: 86.Bl -tag -width indent -offset indent 87.It Em fdesc 88an implementation of /dev/fd 89.It Em isofs 90an ISO 9660 CD-ROM filesystem 91.It Em kernfs 92various and sundry kernel statistics 93.It Em mfs 94a local memory-based 95.Tn UNIX 96filesystem 97.It Em msdos 98a MSDOS ``FAT'' filesystem 99.It Em nfs 100a Sun Microsystems compatible ``Network File System'' 101.It Em procfs 102a local filesystem of process information 103.It Em swap 104a disk partition to be used for swapping 105.It Em ufs 106a local 107.Tn UNIX 108filesystem 109.El 110.Pp 111The fourth field, 112.Pq Fa fs_mntops , 113describes the mount options associated with the filesystem. 114It is formatted as a comma separated list of options. 115It contains at least the type of mount (see 116.Fa fs_type 117below) plus any additional options 118appropriate to the filesystem type. 119.Pp 120If the options ``userquota'' and/or ``groupquota'' are specified, 121the filesystem is automatically processed by the 122.Xr quotacheck 8 123command, and user and/or group disk quotas are enabled with 124.Xr quotaon 8 . 125By default, 126filesystem quotas are maintained in files named 127.Pa quota.user 128and 129.Pa quota.group 130which are located at the root of the associated filesystem. 131These defaults may be overridden by putting an equal sign 132and an alternative absolute pathname following the quota option. 133Thus, if the user quota file for 134.Pa /tmp 135is stored in 136.Pa /var/quotas/tmp.user , 137this location can be specified as: 138.Bd -literal -offset indent 139userquota=/var/quotas/tmp.user 140.Ed 141.Pp 142The type of the mount is extracted from the 143.Fa fs_mntops 144field and stored separately in the 145.Fa fs_type 146field (it is not deleted from the 147.Fa fs_mntops 148field). 149If 150.Fa fs_type 151is ``rw'' or ``ro'' then the filesystem whose name is given in the 152.Fa fs_file 153field is normally mounted read-write or read-only on the 154specified special file. 155If 156.Fa fs_type 157is ``sw'' then the special file is made available as a piece of swap 158space by the 159.Xr swapon 8 160command at the end of the system reboot procedure. 161The fields other than 162.Fa fs_spec 163and 164.Fa fs_type 165are unused. 166If 167.Fa fs_type 168is specified as ``xx'' the entry is ignored. 169This is useful to show disk partitions which are currently unused. 170.Pp 171The fifth field, 172.Pq Fa fs_freq , 173is used for these filesystems by the 174.Xr dump 8 175command to determine which filesystems need to be dumped. 176If the fifth field is not present, a value of zero is returned and 177.Xr dump 178will assume that the filesystem does not need to be dumped. 179.Pp 180The sixth field, 181.Pq Fa fs_passno , 182is used by the 183.Xr fsck 8 184program to determine the order in which filesystem checks are done 185at reboot time. 186The root filesystem should be specified with a 187.Fa fs_passno 188of 1, and other filesystems should have a 189.Fa fs_passno 190of 2. 191Filesystems within a drive will be checked sequentially, 192but filesystems on different drives will be checked at the 193same time to utilize parallelism available in the hardware. 194If the sixth field is not present or zero, 195a value of zero is returned and 196.Xr fsck 197will assume that the filesystem does not need to be checked. 198.Bd -literal 199#define FSTAB_RW "rw" /* read-write device */ 200#define FSTAB_RO "ro" /* read-only device */ 201#define FSTAB_SW "sw" /* swap device */ 202#define FSTAB_XX "xx" /* ignore totally */ 203 204struct fstab { 205 char *fs_spec; /* block special device name */ 206 char *fs_file; /* filesystem path prefix */ 207 char *fs_vfstype; /* type of filesystem */ 208 char *fs_mntops; /* comma separated mount options */ 209 char *fs_type; /* rw, ro, sw, or xx */ 210 int fs_freq; /* dump frequency, in days */ 211 int fs_passno; /* pass number on parallel dump */ 212}; 213.Ed 214.Pp 215The proper way to read records from 216.Pa fstab 217is to use the routines 218.Xr getfsent 3 , 219.Xr getfsspec 3 , 220.Xr getfstype 3 , 221and 222.Xr getfsfile 3 . 223.Sh FILES 224.Bl -tag -width /etc/fstab -compact 225.It Pa /etc/fstab 226The file 227.Nm fstab 228resides in 229.Pa /etc . 230.El 231.Sh SEE ALSO 232.Xr getfsent 3 233.Sh HISTORY 234The 235.Nm 236file format appeared in 237.Bx 4.0 . 238