1.\" $OpenBSD: mount.8,v 1.32 2001/08/13 21:28:35 pvalchev Exp $ 2.\" $NetBSD: mount.8,v 1.11 1995/07/12 06:23:21 cgd Exp $ 3.\" 4.\" Copyright (c) 1980, 1989, 1991, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the University of 18.\" California, Berkeley and its contributors. 19.\" 4. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" @(#)mount.8 8.7 (Berkeley) 3/27/94 36.\" 37.Dd March 27, 1994 38.Dt MOUNT 8 39.Os 40.Sh NAME 41.Nm mount 42.Nd mount file systems 43.Sh SYNOPSIS 44.Nm mount 45.Op Fl Aadfruvw 46.Op Fl t Ar type 47.Nm mount 48.Op Fl dfruvw 49.Ar special | node 50.Nm mount 51.Op Fl dfruvw 52.Op Fl o Ar options 53.Op Fl t Ar type 54.Ar special node 55.Sh DESCRIPTION 56The 57.Nm 58command invokes a filesystem-specific program to prepare 59and graft the 60.Ar special 61device or remote node (rhost:path) on to the file system 62tree at the point 63.Ar node . 64If either 65.Ar special 66or 67.Ar node 68are not provided, the appropriate information is taken from the 69.Xr fstab 5 70file. 71.Pp 72The system maintains a list of currently mounted file systems. 73If no arguments are given to 74.Nm mount , 75this list is printed. 76.Pp 77A mount point 78.Ar node 79must be an existing directory for a mount to succeed 80.Po 81except in the special case of 82.Pa / , 83of course 84.Pc . 85Only the superuser may mount filesystems unless 86.Va kern.usermount 87is nonzero 88.Po 89see 90.Xr sysctl 8 91.Pc . 92.Pp 93The options are as follows: 94.Bl -tag -width Ds 95.It Fl A 96Causes 97.Nm 98to try to mount all of the file systems listed in the 99.Xr fstab 5 100table except those for which the 101.Dq noauto 102option is specified. 103.It Fl a 104Similar to the 105.Fl A 106flag, except that if a file system (other than the root file system) 107appears to be already mounted, 108.Nm 109will not try to mount it again. 110.Nm 111assumes that a file system is already mounted if a file system with 112the same type is mounted on the given mount point. 113More stringent checks are not possible because some file system types 114report strange values for the mounted-from device for mounted file 115systems. 116.It Fl d 117Causes everything to be done except for the invocation of 118the filesystem-specific program. 119This option is useful in conjunction with the 120.Fl v 121flag to 122determine what the 123.Nm 124command is trying to do. 125.It Fl f 126Either force mounting of dirty filesystems or, in the case of a 127downgrade from read-write to read-only operation, the revocation of 128opened files with write access. 129.It Fl o Ar options 130Options are specified with a 131.Fl o 132flag followed by a comma separated string of options. 133Available options are as follows: 134.Bl -tag -width Ds 135.It async 136All 137.Tn I/O 138to the file system should be done asynchronously. 139This is a 140.Em dangerous 141flag to set since it does not guarantee to keep a consistent 142file system structure on the disk. 143You should not use this flag 144unless you are prepared to recreate the file system should your 145system crash. 146The most common use of this flag is to speed up 147.Xr restore 8 148where it can give a factor of two speed increase. 149.It softdep 150(FFS only.) 151Mount the filesystem using soft dependencies. 152Instead of metadata being written immediately, it is written in an ordered 153fashion to keep the on-disk state of the filesystem consistent. 154This results in significant speedups for file create/delete operations. 155This option will be ignored when using the 156.Fl u 157flag and a filesystem is already mounted read/write. 158It requires 159.Cm option FFS_SOFTUPDATES 160to be enabled in the running kernel. 161.It force 162The same as 163.Fl f ; 164forces the revocation of write access when trying to downgrade 165a filesystem mount status from read-write to read-only. 166.It noatime 167Do not update atime on files in the system unless the mtime or ctime 168is being changed as well. 169This option is useful for laptops and news servers where one does 170not want the extra disk activity associated with updating the atime. 171.It noaccesstime 172Synonym for noatime provided for compatibility with 173other operating systems. 174.It nodev 175Do not interpret character or block special devices on the file system. 176This option is useful for a server that has file systems containing 177special devices for architectures other than its own. 178.It noexec 179Do not allow execution of any binaries on the mounted file system. 180This option is useful for a server that has file systems containing 181binaries for architectures other than its own. 182.It nosuid 183Do not allow set-user-identifier or set-group-identifier bits to take effect. 184.It rdonly 185The same as 186.Fl r ; 187mount the file system read-only (even the superuser may not write it). 188.It sync 189All 190.Tn I/O 191to the file system should be done synchronously. 192.It update 193The same as 194.Fl u ; 195indicate that the status of an already mounted file system should be changed. 196.It union 197Causes the namespace at the mount point to appear as the union 198of the mounted filesystem root and the existing directory. 199Lookups will be done in the mounted filesystem first. 200If those operations fail due to a non-existent file the underlying 201directory is then accessed. 202All creates are done in the mounted filesystem. 203.El 204.Pp 205Any additional options specific to a given filesystem type (see the 206.Fl t 207option) may be passed as a comma separated list; these options are 208distinguished by a leading 209.Dq \&- 210(dash). 211Options that take a value are specified using the syntax -option=value. 212For example, the 213.Nm 214command: 215.Bd -literal -offset indent 216mount -t mfs -o nosuid,-N,-s=4000 /dev/dk0b /tmp 217.Ed 218.Pp 219causes 220.Nm 221to execute the equivalent of: 222.Bd -literal -offset indent 223/sbin/mount_mfs -o nosuid -N -s 4000 /dev/dk0b /tmp 224.Ed 225.It Fl r 226The file system is to be mounted read-only. 227Mount the file system read-only (even the superuser may not write it). 228The same as the 229.Dq rdonly 230argument to the 231.Fl o 232option. 233.It Fl t Ar type 234The argument following the 235.Fl t 236is used to indicate the file system type. 237The type 238.Ar ffs 239is the default. 240The 241.Fl t 242option can be used 243to indicate that the actions should only be taken on 244filesystems of the specified type. 245More than one type may be specified in a comma separated list. 246The list of filesystem types can be prefixed with 247.Dq no 248to specify the filesystem types for which action should 249.Em not 250be taken. 251For example, the 252.Nm 253command: 254.Bd -literal -offset indent 255mount -a -t nonfs,mfs 256.Ed 257.Pp 258mounts all filesystems except those of type 259.Tn NFS 260and 261.Tn MFS . 262.Pp 263.Nm 264will attempt to execute a program in 265.Pa /sbin/mount_ Ns Em XXX 266where 267.Em XXX 268is replaced by the type name. 269For example, nfs filesystems are mounted by the program 270.Pa /sbin/mount_nfs . 271.It Fl u 272The 273.Fl u 274flag indicates that the status of an already mounted file 275system should be changed. 276Any of the options discussed above (the 277.Fl o 278option) 279may be changed; 280also a file system can be changed from read-only to read-write 281or vice versa. 282An attempt to change from read-write to read-only will fail if any 283files on the filesystem are currently open for writing unless the 284.Fl f 285flag is also specified. 286The filesystem options are set to those specified in the command line. 287The options set in the 288.Xr fstab 5 289table are ignored. 290.It Fl v 291Verbose mode. 292.It Fl w 293The file system object is to be read and write. 294.El 295.Pp 296The options specific to the various file system types are 297described in the manual pages for those file systems' 298.Nm mount_XXX 299commands. 300For instance, the options specific to Berkeley 301Fast File Systems are described in the 302.Xr mount_ffs 8 303manual page. 304.Sh EXAMPLES 305.Bd -literal 306mount -t cd9660 -r /dev/cd0a /mnt/cdrom 307mount -t msdos /dev/fd0a /mnt/floppy 308mount host:/path/name /mnt/nfs 309.Ed 310.Sh FILES 311.Bl -tag -width /etc/fstab -compact 312.It Pa /etc/fstab 313file system table 314.El 315.Sh SEE ALSO 316.Xr mount 2 , 317.Xr fstab 5 , 318.Xr mount_ados 8 , 319.Xr mount_cd9660 8 , 320.Xr mount_ext2fs 8 , 321.Xr mount_fdesc 8 , 322.Xr mount_ffs 8 , 323.Xr mount_kernfs 8 , 324.Xr mount_mfs 8 , 325.Xr mount_msdos 8 , 326.Xr mount_nfs 8 , 327.Xr mount_null 8 , 328.Xr mount_portal 8 , 329.Xr mount_procfs 8 , 330.Xr mount_umap 8 , 331.Xr mount_union 8 , 332.Xr mount_xfs 8 , 333.Xr sysctl 8 , 334.Xr umount 8 335.Sh HISTORY 336A 337.Nm 338command appeared in 339.At v6 . 340