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 8.8 (Berkeley) 6/16/94 33.\" $Id: mount.8,v 1.14 1997/02/22 14:32:43 peter Exp $ 34.\" 35.Dd June 16, 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 79All the filesystems described in 80.Xr fstab 5 81are mounted. 82Exceptions are those marked as ``noauto'' or are excluded by the 83.Fl t 84flag (see below). 85.It Fl d 86Causes everything to be done except for the actual system call. 87This option is useful in conjunction with the 88.Fl v 89flag to 90determine what the 91.Nm mount 92command is trying to do. 93.It Fl f 94Forces the revocation of write access when trying to downgrade 95a filesystem mount status from read-write to read-only. Also 96forces the R/W mount of an unclean filesystem (dangerous; use with 97caution). 98.It Fl o 99Options are specified with a 100.Fl o 101flag followed by a comma separated string of options. 102The following options are available: 103.Bl -tag -width indent 104.It async 105All 106.Tn I/O 107to the file system should be done asynchronously. 108This is a 109.Em dangerous 110flag to set, 111and should not be used unless you are prepared to recreate the file 112system should your system crash. 113.It force 114The same as 115.Fl f ; 116forces the revocation of write access when trying to downgrade 117a filesystem mount status from read-write to read-only. Also 118forces the R/W mount of an unclean filesystem (dangerous; use with caution). 119.It noatime 120Do not update the file access time when reading from a file. This option 121is useful on filesystems where there are large numbers of files and 122performance is more critical than updating the file access time (which is 123rarely ever important). This option is currently only supported on local 124filesystems. 125.It noauto 126This filesystem should be skipped when mount is run with the 127.Fl a 128flag. 129.It nodev 130Do not interpret character or block special devices on the file system. 131This option is useful for a server that has file systems containing 132special devices for architectures other than its own. 133.It noexec 134Do not allow execution of any binaries on the mounted file system. 135This option is useful for a server that has file systems containing 136binaries for architectures other than its own. 137.It nosuid 138Do not allow set-user-identifier or set-group-identifier bits to take effect. 139Note: this option is worthless if a public available suid or sgid 140wrapper like 141.Xr suidperl 142is installed on your system. 143.It rdonly 144The same as 145.Fl r ; 146mount the file system read-only (even the super-user may not write it). 147.It sync 148All 149.Tn I/O 150to the file system should be done synchronously. 151.It update 152The same as 153.Fl u ; 154indicate that the status of an already mounted file system should be changed. 155.It union 156Causes the namespace at the mount point to appear as the union 157of the mounted filesystem root and the existing directory. 158Lookups will be done in the mounted filesystem first. 159If those operations fail due to a non-existent file the underlying 160directory is then accessed. 161All creates are done in the mounted filesystem. 162.El 163.Pp 164Any additional options specific to a filesystem type that is not 165one of the internally known types (see the 166.Fl t 167option) may be passed as a comma separated list; these options are 168distinguished by a leading 169.Dq \&- 170(dash). 171Options that take a value are specified using the syntax -option=value. 172For example, the mount command: 173.Bd -literal -offset indent 174mount -t mfs -o nosuid,-N,-s=4000 /dev/dk0b /tmp 175.Ed 176.Pp 177causes 178.Nm mount 179to execute the equivalent of: 180.Bd -literal -offset indent 181/sbin/mount_mfs -o nosuid -N -s 4000 /dev/dk0b /tmp 182.Ed 183.It Fl p 184Print mount information in fstab format. Implies also the 185.Fl v 186option. 187.It Fl r 188The file system is to be mounted read-only. 189Mount the file system read-only (even the super-user may not write it). 190The same as the 191.Dq rdonly 192argument to the 193.Fl o 194option. 195.It Fl t Ar "ufs \\*(Ba lfs \\*(Ba external type" 196The argument following the 197.Fl t 198is used to indicate the file system type. 199The type 200.Ar ufs 201is the default. 202The 203.Fl t 204option can be used 205to indicate that the actions should only be taken on 206filesystems of the specified type. 207More than one type may be specified in a comma separated list. 208The list of filesystem types can be prefixed with 209.Dq no 210to specify the filesystem types for which action should 211.Em not 212be taken. 213For example, the 214.Nm mount 215command: 216.Bd -literal -offset indent 217mount -a -t nonfs,mfs 218.Ed 219.Pp 220mounts all filesystems except those of type 221.Tn NFS 222and 223.Tn MFS . 224.Pp 225If the type is not one of the internally known types, 226mount will attempt to execute a program in 227.Pa /sbin/mount_ Ns Em XXX 228where 229.Em XXX 230is replaced by the type name. 231For example, nfs filesystems are mounted by the program 232.Pa /sbin/mount_nfs . 233.Pp 234Most filesystems will be dynamically loaded by their mount programs 235if not already present in the kernel, using the 236.Xr vfsload 3 237subroutine. Because this mechanism requires writable temporary space, 238the filesystem type containing 239.Pa /tmp 240must be compiled into the kernel, and the filesystems containing 241.Pa /tmp 242and 243.Pa /usr/bin/ld 244must be listed in 245.Pa /etc/fstab 246before any filesystems which might be dynamically loaded. 247.It Fl u 248The 249.Fl u 250flag indicates that the status of an already mounted file 251system should be changed. 252Any of the options discussed above (the 253.Fl o 254option) 255may be changed; 256also a file system can be changed from read-only to read-write 257or vice versa. 258An attempt to change from read-write to read-only will fail if any 259files on the filesystem are currently open for writing unless the 260.Fl f 261flag is also specified. 262The set of options is determined by first extracting the options 263for the file system from the 264.Xr fstab 265table, 266then applying any options specified by the 267.Fl o 268argument, 269and finally applying the 270.Fl r 271or 272.Fl w 273option. 274.It Fl v 275Verbose mode. 276.It Fl w 277The file system object is to be read and write. 278.Pp 279The options specific to NFS filesystems are described in the 280.Xr mount_nfs 8 281manual page. 282.Sh FILES 283.Bl -tag -width /etc/fstab -compact 284.It Pa /etc/fstab 285file system table 286.El 287.Sh SEE ALSO 288.Xr mount 2 , 289.Xr vfsload 3 , 290.Xr fstab 5 , 291.Xr mount_cd9660 8 , 292.Xr mount_fdesc 8 , 293.Xr mount_kernfs 8 , 294.Xr mount_lfs 8 , 295.Xr mount_mfs 8 , 296.Xr mount_msdos 8 , 297.Xr mount_nfs 8 , 298.Xr mount_null 8 , 299.Xr mount_portal 8 , 300.Xr mount_procfs 8 , 301.Xr mount_umap 8 , 302.Xr mount_union 8 , 303.Xr umount 8 304.Sh BUGS 305It is possible for a corrupted file system to cause a crash. 306.Sh HISTORY 307A 308.Nm mount 309command appeared in 310.At v1 . 311