1.\" $NetBSD: mount.8,v 1.39 2002/11/07 12:45:35 wiz Exp $ 2.\" 3.\" Copyright (c) 1980, 1989, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)mount.8 8.8 (Berkeley) 6/16/94 35.\" 36.Dd May 21, 2002 37.Dt MOUNT 8 38.Os 39.Sh NAME 40.Nm mount 41.Nd mount file systems 42.Sh SYNOPSIS 43.Nm 44.Op Fl Aadfruvw 45.Op Fl t Ar type 46.Nm "" 47.Op Fl dfruvw 48.Ar special | node 49.Nm "" 50.Op Fl dfruvw 51.Op Fl o Ar options 52.Op Fl t Ar type 53.Ar special node 54.Sh DESCRIPTION 55The 56.Nm 57command invokes a filesystem-specific program to prepare and graft the 58.Ar special 59device or remote node (rhost:path) on to the file system tree at the point 60.Ar node . 61If either 62.Ar special 63or 64.Ar node 65are not provided, the appropriate information is taken from the 66.Xr fstab 5 67file. 68The provided argument is looked up first in the 69.Dq fs_file , 70then in the 71.Dq fs_spec 72column. 73If both 74.Ar special 75and 76.Ar node 77are given, the disklabel is checked for the filesystem type. 78.Pp 79In 80.Nx , 81a file system can only be mounted by an ordinary user who owns the 82point 83.Ar node 84and has access to the 85.Ar special 86device (at least read permissions). 87In addition, the 88.Em vfs.generic.usermount 89.Xr sysctl 3 90must be set to 1 to permit file system mounting by ordinary users. 91See also 92.Xr sysctl 8 . 93.Pp 94The system maintains a list of currently mounted file systems. 95If no arguments are given to 96.Nm "" , 97this list is printed. 98.Pp 99The options are as follows: 100.Bl -tag -width indent 101.It Fl A 102Causes 103.Nm 104to try to mount all of the file systems listed in the 105.Xr fstab 5 106file except those for which the 107.Dq noauto 108option is specified. 109.It Fl a 110Similar to the 111.Fl A 112flag, except that if a file system (other than the root file system) 113appears to be already mounted, 114.Nm 115will not try to mount it again. 116.Nm 117assumes that a file system is already mounted if a file system with 118the same type is mounted on the given mount point. 119More stringent checks are not possible because some file system types 120report strange values for the mounted-from device for mounted file 121systems. 122.It Fl d 123Causes everything to be done except for the invocation of 124the filesystem-specific program. 125This option is useful in conjunction with the 126.Fl v 127flag to determine what the 128.Nm 129command is trying to do. 130.It Fl f 131Forces the revocation of write access when trying to downgrade 132a filesystem mount status from read-write to read-only. 133.It Fl o 134Options are specified with a 135.Fl o 136flag followed by a comma separated string of options. 137The following options are available: 138.Bl -tag -width nocoredump 139.It Cm async 140All 141.Tn I/O 142to the file system should be done asynchronously. 143In the event of a crash, 144.Em "it is impossible for the system to verify the integrity of data on a file system mounted with this option" . 145You should only use this option if you have an application-specific data 146recovery mechanism, or are willing to recreate the file system from scratch. 147.It Cm noasync 148Clear 149.Cm async 150mode. 151.It Cm force 152The same as 153.Fl f ; 154forces the revocation of write access when trying to downgrade 155a filesystem mount status from read-write to read-only. 156.It Cm getargs 157Retrieves the filesystem specific mount arguments for the given 158mounted filesystem and prints them. 159.It Cm noatime 160Never update the access time field for files. 161This option is useful for optimizing read performance on filesystems 162that are used as news spools. 163.It Cm noauto 164This filesystem should be skipped when mount is run with the 165.Fl a 166flag. 167.It Cm nodev 168Do not interpret character or block special devices on the file system. 169This option is useful for a server that has file systems containing 170special devices for architectures other than its own. 171.It Cm nodevmtime 172Do not update modification times on device special files. 173This option is useful on laptops 174or other systems that perform power management. 175.It Cm nocoredump 176Do not allow programs to create crash dumps (core files) on the file system. 177This option can be used to help protect sensitive 178data by keeping core files (which may contain sensitive data) 179from being created on insecure file systems. 180Only core files that would be created by program crashes are 181prevented by use of this flag; the behavior of 182.Xr savecore 8 183is not affected. 184.It Cm noexec 185Do not allow execution of any binaries on the mounted file system. 186This option is useful for a server that has file systems containing 187binaries for architectures other than its own. 188.It Cm hidden 189By setting the 190.Dv MNT_IGNORE 191flag, 192causes the mount point to be excluded from the 193list of filesystems shown by default with 194.Xr df 1 . 195.It Cm nosuid 196Do not allow set-user-identifier or set-group-identifier bits to take effect. 197.It Cm rdonly 198The same as 199.Fl r ; 200mount the file system read-only (even the super-user may not write it). 201.It Cm softdep 202(FFS only) Mount the filesystem using soft-dependencies. 203This means that metadata will not be written immediately, 204but is written in an ordered fashion to keep the 205on-disk state of the filesystem consistent. 206This results in significant speedups for file create/delete operations. 207This option will be ignored when using the 208.Fl u 209flag and a filesystem is already mounted read/write. 210This option has gone through moderate to heavy testing, 211but should still be used with care. 212It requires the 213.Dv SOFTDEP 214option to be enabled in the running kernel. 215.It Cm symperm 216Recognize permission of symbolic link when reading or traversing link. 217.It Cm sync 218All 219.Tn I/O 220to the file system should be done synchronously. 221This is not equivalent to the normal mode in which only 222metadata is written synchronously. 223.It Cm nosync 224Clear 225.Cm sync 226mode. 227.It Cm update 228The same as 229.Fl u ; 230indicate that the status of an already mounted file system should be changed. 231.It Cm union 232Causes the namespace at the mount point to appear as the union 233of the mounted filesystem root and the existing directory. 234Lookups will be done in the mounted filesystem first. 235If those operations fail due to a non-existent file the underlying 236directory is then accessed. 237All creates are done in the mounted filesystem, except for the fdesc 238file system. 239.El 240.Pp 241Any additional options specific to a given filesystem type (see the 242.Fl t 243option) may be passed as a comma separated list; these options are 244distinguished by a leading 245.Dq \&- 246(dash). 247Options that take a value are specified using the syntax -option=value. 248For example, the mount command: 249.Bd -literal -offset indent 250mount -t mfs -o nosuid,-N,-s=32m swap /tmp 251.Ed 252.Pp 253causes 254.Nm 255to execute the equivalent of: 256.Bd -literal -offset indent 257/sbin/mount_mfs -o nosuid -N -s 32m swap /tmp 258.Ed 259.It Fl r 260The file system is to be mounted read-only. 261Mount the file system read-only (even the super-user may not write it). 262The same as the 263.Dq rdonly 264argument to the 265.Fl o 266option. 267.It Fl t Ar type 268The argument following the 269.Fl t 270is used to indicate the file system type. 271The type 272.Ar ffs 273is the default. 274The 275.Fl t 276option can be used to indicate that the actions 277should only be taken on filesystems of the specified type. 278More than one type may be specified in a comma separated list. 279The list of filesystem types can be prefixed with 280.Dq no 281to specify the filesystem types for which action should 282.Em not 283be taken. 284For example, the 285.Nm 286command: 287.Bd -literal -offset indent 288mount -a -t nonfs,mfs 289.Ed 290.Pp 291mounts all filesystems except those of type 292.Tn NFS 293and 294.Tn MFS . 295.Pp 296.Nm 297will attempt to execute a program in 298.Pa /sbin/mount_ Ns Em XXX 299where 300.Em XXX 301is replaced by the type name. 302For example, nfs filesystems are mounted by the program 303.Pa /sbin/mount_nfs . 304.It Fl u 305The 306.Fl u 307flag indicates that the status of an already mounted file 308system should be changed. 309Any of the options discussed above (the 310.Fl o 311option) 312may be changed; 313also a file system can be changed from read-only to read-write 314or vice versa. 315An attempt to change from read-write to read-only will fail if any 316files on the filesystem are currently open for writing unless the 317.Fl f 318flag is also specified. 319The set of options is determined by first extracting the options 320for the file system from the 321.Xr fstab 5 322file, then applying any options specified by the 323.Fl o 324argument, 325and finally applying the 326.Fl r 327or 328.Fl w 329option. 330.It Fl v 331Verbose mode. 332If this flag is specified more than once, then the 333filesystem-specific mount arguments are printed for the given mounted 334filesystem. 335.It Fl w 336The file system object is to be read and write. 337.El 338.Pp 339The options specific to the various file system types are 340described in the manual pages for those file systems' 341.Nm mount_XXX 342commands. 343For instance the options specific to Berkeley 344Fast File System (FFS) are described in the 345.Xr mount_ffs 8 346manual page. 347.Pp 348The particular type of filesystem in each partition of a disk can 349be found by examining the disk label with the 350.Xr disklabel 8 351command. 352.Sh FILES 353.Bl -tag -width /etc/fstab -compact 354.It Pa /etc/fstab 355file system table 356.El 357.Sh EXAMPLES 358Some useful examples: 359.Pp 360.Bl -hang -offset indent -width "MS-DOS" 361.It Tn CD-ROM 362.br 363mount -t cd9660 -r /dev/cd0a /cdrom 364.It Tn MS-DOS 365.br 366mount -t msdos /dev/fd0a /floppy 367.It Tn NFS 368.br 369mount nfs-server-host:/directory/path /mount-point 370.It Tn MFS (32 megabyte) 371.br 372mount -t mfs -o nosuid,-s=32m swap /tmp 373.El 374.Pp 375The "noauto" directive in 376.Pa /etc/fstab 377can be used to make it easy to manually mount and unmount removeable 378media using just the mountpoint filename, with an entry like this: 379.Pp 380.Dl /dev/cd0a /cdrom cd9660 ro,noauto 0 0 381.Pp 382That would allow a simple command like 383.Qq mount /cdrom 384or 385.Qq umount /cdrom 386for media using the 387.Tn ISO-9660 388filesystem format in the first 389.Tn CD-ROM 390drive. 391.Sh SEE ALSO 392.Xr df 1 , 393.Xr mount 2 , 394.Xr fstab 5 , 395.Xr disklabel 8 , 396.Xr mount_ados 8 , 397.Xr mount_cd9660 8 , 398.Xr mount_ext2fs 8 , 399.Xr mount_fdesc 8 , 400.Xr mount_ffs 8 , 401.Xr mount_filecore 8 , 402.Xr mount_kernfs 8 , 403.Xr mount_lfs 8 , 404.Xr mount_mfs 8 , 405.Xr mount_msdos 8 , 406.Xr mount_nfs 8 , 407.Xr mount_ntfs 8 , 408.Xr mount_null 8 , 409.Xr mount_overlay 8 , 410.Xr mount_portal 8 , 411.Xr mount_procfs 8 , 412.Xr mount_umap 8 , 413.Xr mount_union 8 , 414.Xr umount 8 415.Sh HISTORY 416A 417.Nm 418command appeared in 419.At v6 . 420