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.\" 34.Dd March 27, 1994 35.Dt MOUNT 8 36.Os BSD 4 37.Sh NAME 38.Nm mount 39.Nd mount file systems 40.Sh SYNOPSIS 41.Nm mount 42.Op Fl adfruvw 43.Op Fl t Ar ufs | lfs | external_type 44.Nm mount 45.Op Fl dfruvw 46.Ar special | node 47.Nm mount 48.Op Fl dfruvw 49.Op Fl o Ar options 50.Op Fl t Ar ufs | lfs | external_type 51.Ar special node 52.Sh DESCRIPTION 53The 54.Nm mount 55command 56calls the 57.Xr mount 2 58system call to prepare and graft a 59.Ar "special device" 60or the remote node (rhost:path) on to the file system tree at the point 61.Ar node . 62If either 63.Ar special 64or 65.Ar node 66are not provided, the appropriate information is taken from the 67.Xr fstab 5 68file. 69.Pp 70The system maintains a list of currently mounted file systems. 71If no arguments are given to 72.Nm mount, 73this list is printed. 74.Pp 75The options are as follows: 76.Bl -tag -width indent 77.It Fl d 78Causes everything to be done except for the actual system call. 79This option is useful in conjunction with the 80.Fl v 81flag to 82determine what the 83.Nm mount 84command is trying to do. 85.It Fl f 86Forces the revocation of write access when trying to downgrade 87a filesystem mount status from read-write to read-only. Also 88forces the R/W mount of an unclean filesystem (dangerous; use with 89caution). 90.It Fl o 91Options are specified with a 92.Fl o 93flag followed by a comma separated string of options. 94The following options are available: 95.Bl -tag -width indent 96.It async 97All 98.Tn I/O 99to the file system should be done asynchronously. 100This is a 101.Em dangerous 102flag to set, 103and should not be used unless you are prepared to recreate the file 104system should your system crash. 105.It force 106The same as 107.Fl f ; 108forces the revocation of write access when trying to downgrade 109a filesystem mount status from read-write to read-only. Also 110forces the R/W mount of an unclean filesystem (dangerous; use with caution). 111.It nodev 112Do not interpret character or block special devices on the file system. 113This option is useful for a server that has file systems containing 114special devices for architectures other than its own. 115.It noexec 116Do not allow execution of any binaries on the mounted file system. 117This option is useful for a server that has file systems containing 118binaries for architectures other than its own. 119.It nosuid 120Do not allow set-user-identifier or set-group-identifier bits to take effect. 121.It rdonly 122The same as 123.Fl r ; 124mount the file system read-only (even the super-user may not write it). 125.It sync 126All 127.Tn I/O 128to the file system should be done synchronously. 129.It update 130The same as 131.Fl u ; 132indicate that the status of an already mounted file system should be changed. 133.It union 134Causes the namespace at the mount point to appear as the union 135of the mounted filesystem root and the existing directory. 136Lookups will be done in the mounted filesystem first. 137If those operations fail due to a non-existent file the underlying 138directory is then accessed. 139All creates are done in the mounted filesystem. 140.El 141.Pp 142Any additional options specific to a filesystem type that is not 143one of the internally known types (see the 144.Fl t 145option) may be passed as a comma separated list; these options are 146distinguished by a leading 147.Dq \&- 148(dash). 149Options that take a value are specified using the syntax -option=value. 150For example, the mount command: 151.Bd -literal -offset indent 152mount -t mfs -o nosuid,-N,-s=4000 /dev/dk0b /tmp 153.Ed 154.Pp 155causes 156.Nm mount 157to execute the equivalent of: 158.Bd -literal -offset indent 159/sbin/mount_mfs -o nosuid -N -s 4000 /dev/dk0b /tmp 160.Ed 161.It Fl r 162The file system is to be mounted read-only. 163Mount the file system read-only (even the super-user may not write it). 164The same as the 165.Dq rdonly 166argument to the 167.Fl o 168option. 169.It Fl t Ar "ufs \\*(Ba lfs \\*(Ba external type" 170The argument following the 171.Fl t 172is used to indicate the file system type. 173The type 174.Ar ufs 175is the default. 176The 177.Fl t 178option can be used 179to indicate that the actions should only be taken on 180filesystems of the specified type. 181More than one type may be specified in a comma separated list. 182The list of filesystem types can be prefixed with 183.Dq no 184to specify the filesystem types for which action should 185.Em not 186be taken. 187For example, the 188.Nm mount 189command: 190.Bd -literal -offset indent 191mount -a -t nonfs,mfs 192.Ed 193.Pp 194mounts all filesystems except those of type 195.Tn NFS 196and 197.Tn MFS . 198.Pp 199If the type is not one of the internally known types, 200mount will attempt to execute a program in 201.Pa /sbin/mount_ Ns Em XXX 202where 203.Em XXX 204is replaced by the type name. 205For example, nfs filesystems are mounted by the program 206.Pa /sbin/mount_nfs . 207.Pp 208Most filesystems will be dynamically loaded by their mount programs 209if not already present in the kernel, using the 210.Xr vfsload 3 211subroutine. Because this mechanism requires writable temporary space, 212the filesystem type containing 213.Pa /tmp 214must be compiled into the kernel, and the filesystems containing 215.Pa /tmp 216and 217.Pa /usr/bin/ld 218must be listed in 219.Pa /etc/fstab 220before any filesystems which might be dynamically loaded. 221.It Fl u 222The 223.Fl u 224flag indicates that the status of an already mounted file 225system should be changed. 226Any of the options discussed above (the 227.Fl o 228option) 229may be changed; 230also a file system can be changed from read-only to read-write 231or vice versa. 232An attempt to change from read-write to read-only will fail if any 233files on the filesystem are currently open for writing unless the 234.Fl f 235flag is also specified. 236The set of options is determined by first extracting the options 237for the file system from the 238.Xr fstab 239table, 240then applying any options specified by the 241.Fl o 242argument, 243and finally applying the 244.Fl r 245or 246.Fl w 247option. 248.It Fl v 249Verbose mode. 250.It Fl w 251The file system object is to be read and write. 252.Pp 253The options specific to NFS filesystems are described in the 254.Xr mount_nfs 8 255manual page. 256.Sh FILES 257.Bl -tag -width /etc/fstab -compact 258.It Pa /etc/fstab 259file system table 260.El 261.Sh SEE ALSO 262.Xr mount 2 , 263.Xr vfsload 3 , 264.Xr fstab 5 , 265.Xr mount_cd9660 8 , 266.Xr mount_fdesc 8 , 267.Xr mount_kernfs 8 , 268.Xr mount_lfs 8 , 269.Xr mount_lofs 8 , 270.Xr mount_mfs 8 , 271.Xr mount_nfs 8 , 272.Xr mount_null 8 , 273.Xr mount_portal 8 , 274.Xr mount_procfs 8 , 275.Xr mount_umap 8 , 276.Xr mount_union 8 , 277.Xr umount 8 278.Sh BUGS 279It is possible for a corrupted file system to cause a crash. 280.Sh HISTORY 281A 282.Nm mount 283command appeared in 284.At v6 . 285