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. 88.It Fl o 89Options are specified with a 90.Fl o 91flag followed by a comma separated string of options. 92The following options are available: 93.Bl -tag -width indent 94.It async 95All 96.Tn I/O 97to the file system should be done asynchronously. 98This is a 99.Em dangerous 100flag to set, 101and should not be used unless you are prepared to recreate the file 102system should your system crash. 103.It force 104The same as 105.Fl f ; 106forces the revocation of write access when trying to downgrade 107a filesystem mount status from read-write to read-only. 108.It nodev 109Do not interpret character or block special devices on the file system. 110This option is useful for a server that has file systems containing 111special devices for architectures other than its own. 112.It noexec 113Do not allow execution of any binaries on the mounted file system. 114This option is useful for a server that has file systems containing 115binaries for architectures other than its own. 116.It nosuid 117Do not allow set-user-identifier or set-group-identifier bits to take effect. 118.It rdonly 119The same as 120.Fl r ; 121mount the file system read-only (even the super-user may not write it). 122.It sync 123All 124.Tn I/O 125to the file system should be done synchronously. 126.It update 127The same as 128.Fl u ; 129indicate that the status of an already mounted file system should be changed. 130.It union 131Causes the namespace at the mount point to appear as the union 132of the mounted filesystem root and the existing directory. 133Lookups will be done in the mounted filesystem first. 134If those operations fail due to a non-existent file the underlying 135directory is then accessed. 136All creates are done in the mounted filesystem. 137.El 138.Pp 139Any additional options specific to a filesystem type that is not 140one of the internally known types (see the 141.Fl t 142option) may be passed as a comma separated list; these options are 143distinguished by a leading 144.Dq \&- 145(dash). 146Options that take a value are specified using the syntax -option=value. 147For example, the mount command: 148.Bd -literal -offset indent 149mount -t mfs -o nosuid,-N,-s=4000 /dev/dk0b /tmp 150.Ed 151.Pp 152causes 153.Nm mount 154to execute the equivalent of: 155.Bd -literal -offset indent 156/sbin/mount_mfs -o nosuid -N -s 4000 /dev/dk0b /tmp 157.Ed 158.It Fl r 159The file system is to be mounted read-only. 160Mount the file system read-only (even the super-user may not write it). 161The same as the 162.Dq rdonly 163argument to the 164.Fl o 165option. 166.It Fl t Ar "ufs \\*(Ba lfs \\*(Ba external type" 167The argument following the 168.Fl t 169is used to indicate the file system type. 170The type 171.Ar ufs 172is the default. 173The \fI-t\fP option can be used 174to indicate that the actions should only be taken on 175filesystems of the specified type. 176More than one type may be specified in a comma separated list. 177The list of filesystem types can be prefixed with 178.Dq no 179to specify the filesystem types for which action should 180.Em not 181be taken. 182For example, the 183.Nm mount 184command: 185.Bd -literal -offset indent 186mount -a -t nonfs,mfs 187.Ed 188.Pp 189mounts all filesystems except those of type 190.Tn NFS 191and 192.Tn MFS . 193.Pp 194If the type is not one of the internally known types, 195mount will attempt to execute a program in 196.Pa /sbin/mount_ Ns Em XXX 197where 198.Em XXX 199is replaced by the type name. 200For example, nfs filesystems are mounted by the program 201.Pa /sbin/mount_nfs . 202.It Fl u 203The 204.Fl u 205flag indicates that the status of an already mounted file 206system should be changed. 207Any of the options discussed above (the 208.Fl o 209option) 210may be changed; 211also a file system can be changed from read-only to read-write 212or vice versa. 213An attempt to change from read-write to read-only will fail if any 214files on the filesystem are currently open for writing unless the 215.Fl f 216flag is also specified. 217The set of options is determined by first extracting the options 218for the file system from the 219.Xr fstab 220table, 221then applying any options specified by the 222.Fl o 223argument, 224and finally applying the 225.Fl r 226or 227.Fl w 228option. 229.It Fl v 230Verbose mode. 231.It Fl w 232The file system object is to be read and write. 233.Pp 234The options specific to NFS filesystems are described in the 235.Xr mount_nfs 8 236manual page. 237.Sh FILES 238.Bl -tag -width /etc/fstab -compact 239.It Pa /etc/fstab 240file system table 241.El 242.Sh SEE ALSO 243.Xr mount 2 , 244.Xr fstab 5 , 245.Xr mount_cd9660 8 , 246.Xr mount_fdesc 8 , 247.Xr mount_kernfs 8 , 248.Xr mount_lfs 8 , 249.Xr mount_lofs 8 , 250.Xr mount_mfs 8 , 251.Xr mount_nfs 8 , 252.Xr mount_null 8 , 253.Xr mount_portal 8 , 254.Xr mount_procfs 8 , 255.Xr mount_umap 8 , 256.Xr mount_union 8 , 257.Xr umount 8 258.Sh BUGS 259It is possible for a corrupted file system to cause a crash. 260.Sh HISTORY 261A 262.Nm mount 263command appeared in 264.At v6 . 265