1.\" Copyright (c) 1980, 1989, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" %sccs.include.redist.roff% 5.\" 6.\" @(#)mount.8 8.7 (Berkeley) 03/27/94 7.\" 8.Dd 9.Dt MOUNT 8 10.Os BSD 4 11.Sh NAME 12.Nm mount 13.Nd mount file systems 14.Sh SYNOPSIS 15.Nm mount 16.Op Fl adfruvw 17.Op Fl t Ar ufs | lfs | external_type 18.Nm mount 19.Op Fl dfruvw 20.Ar special | node 21.Nm mount 22.Op Fl dfruvw 23.Op Fl o Ar options 24.Op Fl t Ar ufs | lfs | external_type 25.Ar special node 26.Sh DESCRIPTION 27The 28.Nm mount 29command 30calls the 31.Xr mount 2 32system call to prepare and graft a 33.Ar "special device" 34or the remote node (rhost:path) on to the file system tree at the point 35.Ar node . 36If either 37.Ar special 38or 39.Ar node 40are not provided, the appropriate information is taken from the 41.Xr fstab 5 42file. 43.Pp 44The system maintains a list of currently mounted file systems. 45If no arguments are given to 46.Nm mount, 47this list is printed. 48.Pp 49The options are as follows: 50.Bl -tag -width indent 51.It Fl d 52Causes everything to be done except for the actual system call. 53This option is useful in conjunction with the 54.Fl v 55flag to 56determine what the 57.Nm mount 58command is trying to do. 59.It Fl f 60Forces the revocation of write access when trying to downgrade 61a filesystem mount status from read-write to read-only. 62.It Fl o 63Options are specified with a 64.Fl o 65flag followed by a comma separated string of options. 66The following options are available: 67.Bl -tag -width indent 68.It async 69All 70.Tn I/O 71to the file system should be done asynchronously. 72This is a 73.Em dangerous 74flag to set, 75and should not be used unless you are prepared to recreate the file 76system should your system crash. 77.It force 78The same as 79.Fl f ; 80forces the revocation of write access when trying to downgrade 81a filesystem mount status from read-write to read-only. 82.It nodev 83Do not interpret character or block special devices on the file system. 84This option is useful for a server that has file systems containing 85special devices for architectures other than its own. 86.It noexec 87Do not allow execution of any binaries on the mounted file system. 88This option is useful for a server that has file systems containing 89binaries for architectures other than its own. 90.It nosuid 91Do not allow set-user-identifier or set-group-identifier bits to take effect. 92.It rdonly 93The same as 94.Fl r ; 95mount the file system read-only (even the super-user may not write it). 96.It sync 97All 98.Tn I/O 99to the file system should be done synchronously. 100.It update 101The same as 102.Fl u ; 103indicate that the status of an already mounted file system should be changed. 104.It union 105Causes the namespace at the mount point to appear as the union 106of the mounted filesystem root and the existing directory. 107Lookups will be done in the mounted filesystem first. 108If those operations fail due to a non-existent file the underlying 109directory is then accessed. 110All creates are done in the mounted filesystem. 111.El 112.Pp 113Any additional options specific to a filesystem type that is not 114one of the internally known types (see the 115.Fl t 116option) may be passed as a comma separated list; these options are 117distinguished by a leading 118.Dq \&- 119(dash). 120Options that take a value are specified using the syntax -option=value. 121For example, the mount command: 122.Bd -literal -offset indent 123mount -t mfs -o nosuid,-N,-s=4000 /dev/dk0b /tmp 124.Ed 125.Pp 126causes 127.Nm mount 128to execute the equivalent of: 129.Bd -literal -offset indent 130/sbin/mount_mfs -o nosuid -N -s 4000 /dev/dk0b /tmp 131.Ed 132.It Fl r 133The file system is to be mounted read-only. 134Mount the file system read-only (even the super-user may not write it). 135The same as the 136.Dq rdonly 137argument to the 138.Fl o 139option. 140.It Fl t Ar "ufs \\*(Ba lfs \\*(Ba external type" 141The argument following the 142.Fl t 143is used to indicate the file system type. 144The type 145.Ar ufs 146is the default. 147The \fI-t\fP option can be used 148to indicate that the actions should only be taken on 149filesystems of the specified type. 150More than one type may be specified in a comma separated list. 151The list of filesystem types can be prefixed with 152.Dq no 153to specify the filesystem types for which action should 154.Em not 155be taken. 156For example, the 157.Nm mount 158command: 159.Bd -literal -offset indent 160mount -a -t nonfs,mfs 161.Ed 162.Pp 163mounts all filesystems except those of type 164.Tn NFS 165and 166.Tn MFS . 167.Pp 168If the type is not one of the internally known types, 169mount will attempt to execute a program in 170.Pa /sbin/mount_ Ns Em XXX 171where 172.Em XXX 173is replaced by the type name. 174For example, nfs filesystems are mounted by the program 175.Pa /sbin/mount_nfs . 176.It Fl u 177The 178.Fl u 179flag indicates that the status of an already mounted file 180system should be changed. 181Any of the options discussed above (the 182.Fl o 183option) 184may be changed; 185also a file system can be changed from read-only to read-write 186or vice versa. 187An attempt to change from read-write to read-only will fail if any 188files on the filesystem are currently open for writing unless the 189.Fl f 190flag is also specified. 191The set of options is determined by first extracting the options 192for the file system from the 193.Xr fstab 194table, 195then applying any options specified by the 196.Fl o 197argument, 198and finally applying the 199.Fl r 200or 201.Fl w 202option. 203.It Fl v 204Verbose mode. 205.It Fl w 206The file system object is to be read and write. 207.Pp 208The options specific to NFS filesystems are described in the 209.Xr mount_nfs 8 210manual page. 211.Sh FILES 212.Bl -tag -width /etc/fstab -compact 213.It Pa /etc/fstab 214file system table 215.El 216.Sh SEE ALSO 217.Xr mount 2 , 218.Xr fstab 5 , 219.Xr mount_cd9660 8 , 220.Xr mount_fdesc 8 , 221.Xr mount_kernfs 8 , 222.Xr mount_lfs 8 , 223.Xr mount_lofs 8 , 224.Xr mount_mfs 8 , 225.Xr mount_nfs 8 , 226.Xr mount_null 8 , 227.Xr mount_portal 8 , 228.Xr mount_procfs 8 , 229.Xr mount_umap 8 , 230.Xr mount_union 8 , 231.Xr umount 8 232.Sh BUGS 233It is possible for a corrupted file system to cause a crash. 234.Sh HISTORY 235A 236.Nm mount 237command appeared in 238.At v6 . 239