1.\" Copyright (c) 1980, 1989, 1991, 1993 2.\" The Regents of the University of California. 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.\" @(#)mount.8 8.7 (Berkeley) 3/27/94 33.\" $Id: mount.8,v 1.10 1996/08/29 18:06:02 wosch Exp $ 34.\" 35.Dd March 27, 1994 36.Dt MOUNT 8 37.Os BSD 4 38.Sh NAME 39.Nm mount 40.Nd mount file systems 41.Sh SYNOPSIS 42.Nm mount 43.Op Fl adfpruvw 44.Op Fl t Ar ufs | lfs | external_type 45.Nm mount 46.Op Fl dfpruvw 47.Ar special | node 48.Nm mount 49.Op Fl dfpruvw 50.Op Fl o Ar options 51.Op Fl t Ar ufs | lfs | external_type 52.Ar special node 53.Sh DESCRIPTION 54The 55.Nm mount 56command 57calls the 58.Xr mount 2 59system call to prepare and graft a 60.Ar "special device" 61or the remote node (rhost:path) on to the file system tree at the point 62.Ar node . 63If either 64.Ar special 65or 66.Ar node 67are not provided, the appropriate information is taken from the 68.Xr fstab 5 69file. 70.Pp 71The system maintains a list of currently mounted file systems. 72If no arguments are given to 73.Nm mount, 74this list is printed. 75.Pp 76The options are as follows: 77.Bl -tag -width indent 78.It Fl a 79Causes all filesystems listed in 80.Pa /etc/fstab 81(except those with the ``noauto'' option) to be mounted. This is normally 82done during system startup. 83.It Fl d 84Causes everything to be done except for the actual system call. 85This option is useful in conjunction with the 86.Fl v 87flag to 88determine what the 89.Nm mount 90command is trying to do. 91.It Fl f 92Forces the revocation of write access when trying to downgrade 93a filesystem mount status from read-write to read-only. Also 94forces the R/W mount of an unclean filesystem (dangerous; use with 95caution). 96.It Fl o 97Options are specified with a 98.Fl o 99flag followed by a comma separated string of options. 100The following options are available: 101.Bl -tag -width indent 102.It async 103All 104.Tn I/O 105to the file system should be done asynchronously. 106This is a 107.Em dangerous 108flag to set, 109and should not be used unless you are prepared to recreate the file 110system should your system crash. 111.It force 112The same as 113.Fl f ; 114forces the revocation of write access when trying to downgrade 115a filesystem mount status from read-write to read-only. Also 116forces the R/W mount of an unclean filesystem (dangerous; use with caution). 117.It noatime 118Do not update the file access time when reading from a file. This option 119is useful on filesystems where there are large numbers of files and 120performance is more critical than updating the file access time (which is 121rarely ever important). This option is currently only supported on local 122filesystems. 123.It nodev 124Do not interpret character or block special devices on the file system. 125This option is useful for a server that has file systems containing 126special devices for architectures other than its own. 127.It noexec 128Do not allow execution of any binaries on the mounted file system. 129This option is useful for a server that has file systems containing 130binaries for architectures other than its own. 131.It nosuid 132Do not allow set-user-identifier or set-group-identifier bits to take effect. 133Note: this option is worthless if a public available suid or sgid 134wrapper like 135.Xr suidperl 136is installed on your system. 137.It rdonly 138The same as 139.Fl r ; 140mount the file system read-only (even the super-user may not write it). 141.It sync 142All 143.Tn I/O 144to the file system should be done synchronously. 145.It update 146The same as 147.Fl u ; 148indicate that the status of an already mounted file system should be changed. 149.It union 150Causes the namespace at the mount point to appear as the union 151of the mounted filesystem root and the existing directory. 152Lookups will be done in the mounted filesystem first. 153If those operations fail due to a non-existent file the underlying 154directory is then accessed. 155All creates are done in the mounted filesystem. 156.El 157.Pp 158Any additional options specific to a filesystem type that is not 159one of the internally known types (see the 160.Fl t 161option) may be passed as a comma separated list; these options are 162distinguished by a leading 163.Dq \&- 164(dash). 165Options that take a value are specified using the syntax -option=value. 166For example, the mount command: 167.Bd -literal -offset indent 168mount -t mfs -o nosuid,-N,-s=4000 /dev/dk0b /tmp 169.Ed 170.Pp 171causes 172.Nm mount 173to execute the equivalent of: 174.Bd -literal -offset indent 175/sbin/mount_mfs -o nosuid -N -s 4000 /dev/dk0b /tmp 176.Ed 177.It Fl p 178Print mount information in fstab format. Implies also the 179.Fl v 180option. 181.It Fl r 182The file system is to be mounted read-only. 183Mount the file system read-only (even the super-user may not write it). 184The same as the 185.Dq rdonly 186argument to the 187.Fl o 188option. 189.It Fl t Ar "ufs \\*(Ba lfs \\*(Ba external type" 190The argument following the 191.Fl t 192is used to indicate the file system type. 193The type 194.Ar ufs 195is the default. 196The 197.Fl t 198option can be used 199to indicate that the actions should only be taken on 200filesystems of the specified type. 201More than one type may be specified in a comma separated list. 202The list of filesystem types can be prefixed with 203.Dq no 204to specify the filesystem types for which action should 205.Em not 206be taken. 207For example, the 208.Nm mount 209command: 210.Bd -literal -offset indent 211mount -a -t nonfs,mfs 212.Ed 213.Pp 214mounts all filesystems except those of type 215.Tn NFS 216and 217.Tn MFS . 218.Pp 219If the type is not one of the internally known types, 220mount will attempt to execute a program in 221.Pa /sbin/mount_ Ns Em XXX 222where 223.Em XXX 224is replaced by the type name. 225For example, nfs filesystems are mounted by the program 226.Pa /sbin/mount_nfs . 227.Pp 228Most filesystems will be dynamically loaded by their mount programs 229if not already present in the kernel, using the 230.Xr vfsload 3 231subroutine. Because this mechanism requires writable temporary space, 232the filesystem type containing 233.Pa /tmp 234must be compiled into the kernel, and the filesystems containing 235.Pa /tmp 236and 237.Pa /usr/bin/ld 238must be listed in 239.Pa /etc/fstab 240before any filesystems which might be dynamically loaded. 241.It Fl u 242The 243.Fl u 244flag indicates that the status of an already mounted file 245system should be changed. 246Any of the options discussed above (the 247.Fl o 248option) 249may be changed; 250also a file system can be changed from read-only to read-write 251or vice versa. 252An attempt to change from read-write to read-only will fail if any 253files on the filesystem are currently open for writing unless the 254.Fl f 255flag is also specified. 256The set of options is determined by first extracting the options 257for the file system from the 258.Xr fstab 259table, 260then applying any options specified by the 261.Fl o 262argument, 263and finally applying the 264.Fl r 265or 266.Fl w 267option. 268.It Fl v 269Verbose mode. 270.It Fl w 271The file system object is to be read and write. 272.Pp 273The options specific to NFS filesystems are described in the 274.Xr mount_nfs 8 275manual page. 276.Sh FILES 277.Bl -tag -width /etc/fstab -compact 278.It Pa /etc/fstab 279file system table 280.El 281.Sh SEE ALSO 282.Xr mount 2 , 283.Xr vfsload 3 , 284.Xr fstab 5 , 285.Xr mount_cd9660 8 , 286.Xr mount_fdesc 8 , 287.Xr mount_kernfs 8 , 288.Xr mount_lfs 8 , 289.Xr mount_mfs 8 , 290.Xr mount_nfs 8 , 291.Xr mount_null 8 , 292.Xr mount_portal 8 , 293.Xr mount_procfs 8 , 294.Xr mount_umap 8 , 295.Xr mount_union 8 , 296.Xr umount 8 297.Sh BUGS 298It is possible for a corrupted file system to cause a crash. 299.Sh HISTORY 300A 301.Nm mount 302command appeared in 303.At v1 . 304