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. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)mount.8 8.8 (Berkeley) 6/16/94 29.\" $FreeBSD: src/sbin/mount/mount.8,v 1.31.2.12 2003/02/23 21:17:42 trhodes Exp $ 30.\" 31.Dd May 15, 2016 32.Dt MOUNT 8 33.Os 34.Sh NAME 35.Nm mount 36.Nd mount file systems 37.Sh SYNOPSIS 38.Nm 39.Op Fl adfpruvw 40.Op Fl F Ar fstab 41.Op Fl o Ar options 42.Op Fl t Ar type 43.Nm 44.Op Fl dfpruvw 45.Brq Ar special | node 46.Nm 47.Op Fl dfpruvw 48.Op Fl o Ar options 49.Op Fl t Ar type 50.Ar special node 51.Sh DESCRIPTION 52The 53.Nm 54utility calls the 55.Xr mount 2 56system call to prepare and graft a 57.Ar "special device" 58or the remote node (rhost:path) on to the file system tree at the point 59.Ar node . 60If either 61.Ar special 62or 63.Ar node 64are not provided, the appropriate information is taken from the 65.Xr fstab 5 66file. 67.Pp 68The system maintains a list of currently mounted file systems. 69If no arguments are given to 70.Nm , 71this list is printed. 72.Pp 73The options are as follows: 74.Bl -tag -width indent 75.It Fl a 76All the filesystems described in 77.Xr fstab 5 78are mounted. 79Exceptions are those marked as 80.Dq noauto , 81excluded by the 82.Fl t 83flag (see below), or if they are already mounted (except the 84root filesystem which is always remounted to preserve 85traditional single user mode behavior). 86.It Fl d 87Causes everything to be done except for the actual system call. 88This option is useful in conjunction with the 89.Fl v 90flag to 91determine what the 92.Nm 93command is trying to do. 94.It Fl F Ar fstab 95Specify the 96.Pa fstab 97file to use. 98.It Fl f 99Forces the revocation of write access when trying to downgrade 100a filesystem mount status from read-write to read-only. 101Also 102forces the R/W mount of an unclean filesystem (dangerous; use with 103caution). 104.It Fl o 105Options are specified with a 106.Fl o 107flag followed by a comma separated string of options. 108If a 109.Dq no 110prefix is added or removed from a option name, then meaning is negated. 111In case of conflicting options being specified, the rightmost option 112takes effect. 113The following options are available: 114.Bl -tag -width indent 115.It Cm async 116All 117.Tn I/O 118to the file system should be done asynchronously. 119This is a 120.Em dangerous 121flag to set, 122and should not be used unless you are prepared to recreate the file 123system should your system crash. 124.It Cm automounted 125This flag indicates that the file system was mounted by 126.Xr automountd 8 . 127Automounted file systems are automatically unmounted by 128.Xr autounmountd 8 . 129.It Cm current 130When used with the 131.Fl u 132flag, this is the same as specifying the options currently in effect for 133the mounted filesystem. 134.It Cm force 135The same as 136.Fl f ; 137forces the revocation of write access when trying to downgrade 138a filesystem mount status from read-write to read-only. 139Also 140forces the R/W mount of an unclean filesystem (dangerous; use with caution). 141.It Cm fstab 142When used with the 143.Fl u 144flag, this is the same as specifying all the options listed in the 145.Xr fstab 5 146file for the filesystem. 147.It Cm noasync 148Metadata I/O should be done synchronously, while data I/O should be done 149asynchronously. 150This is the default. 151.It Cm noatime 152Do not update the file access time when reading from a file. 153This option 154is useful on filesystems where there are large numbers of files and 155performance is more critical than updating the file access time (which is 156rarely ever important). 157This option is currently only supported on local filesystems. 158.It Cm noauto 159This filesystem should be skipped when 160.Nm 161is run with the 162.Fl a 163flag. 164.It Cm noclusterr 165Disable read clustering. 166.It Cm noclusterw 167Disable write clustering. 168.It Cm nodev 169Do not interpret character or block special devices on the file system. 170This option is useful for a server that has file systems containing 171special devices for architectures other than its own. 172This option is set automatically when the user does not have super-user 173privileges. 174.It Cm noexec 175Do not allow execution of any binaries on the mounted file system. 176This option is useful for a server that has file systems containing 177binaries for architectures other than its own. 178.It Cm nosuid 179Do not allow set-user-identifier or set-group-identifier bits to take effect. 180Note: this option is worthless if a public available suid or sgid 181wrapper like 182.Xr suidperl 1 183is installed on your system. 184It is set automatically when the user does not have super-user privileges. 185.It Cm nosymfollow 186Do not follow symlinks 187on the mounted file system. 188.It Cm rdonly , ro , norw 189The same as 190.Fl r ; 191mount the file system read-only (even the super-user may not write it). 192.It Cm sync 193All 194.Tn I/O 195to the file system should be done synchronously. 196.It Cm trim 197If the device supports TRIM 198.Va ( kern.cam.da.X.trim_enabled 199exists) and is set, 200the file system will perform online trim for corresponding block deletions. 201Currently, only 202.Xr UFS 5 203supports this feature. 204.It Cm suiddir 205A directory on the mounted filesystem will respond to the SUID bit 206being set, by setting the owner of any new files to be the same 207as the owner of the directory. 208New directories will inherit the bit from their parents. 209Execute bits are removed from 210the file, and it will not be given to root. 211.Pp 212This feature is designed for use on fileservers serving PC users via 213ftp or SAMBA. 214It provides security holes for shell users and as 215such should not be used on shell machines, especially on home directories. 216This option requires the SUIDDIR 217option in the kernel to work. 218Only 219.Xr UFS 5 220filesystems support this option. 221See 222.Xr chmod 2 223for more information. 224.It Cm update 225The same as 226.Fl u ; 227indicate that the status of an already mounted file system should be changed. 228.It Cm ignore 229Will be ignored by 230.Xr df 1 . 231.El 232.Pp 233Any additional options specific to a filesystem type that is not 234one of the internally known types (see the 235.Fl t 236option) may be passed as a comma separated list; these options are 237distinguished by a leading 238.Dq \&- 239(dash). 240Options that take a value are specified using the syntax -option=value. 241For example, the 242.Nm 243command: 244.Bd -literal -offset indent 245mount -t mfs -o nosuid,-N,-s=4000 /dev/da0s0b /tmp 246.Ed 247.Pp 248causes 249.Nm 250to execute the equivalent of: 251.Bd -literal -offset indent 252/sbin/mount_mfs -o nosuid -N -s 4000 /dev/da0s0b /tmp 253.Ed 254.Pp 255Additional options specific to filesystem types 256which are not internally known 257(see the description of the 258.Fl t 259option below) 260may be described in the manual pages for the associated 261.Pa /sbin/mount_ Ns Sy XXX 262utilities. 263.It Fl p 264Print mount information in 265.Xr fstab 5 266format. 267If fstab is missing or if the freq and passno fields are omitted, 268the default values as described in 269.Xr fstab 5 270are used. 271Implies also the 272.Fl v 273option. 274.It Fl r 275The file system is to be mounted read-only. 276Mount the file system read-only (even the super-user may not write it). 277The same as the 278.Cm rdonly 279argument to the 280.Fl o 281option. 282.It Fl t Ar type 283The argument following the 284.Fl t 285is used to indicate the file system type. 286The type 287.Cm ufs 288is the default. 289The 290.Fl t 291option can be used 292to indicate that the actions should only be taken on 293filesystems of the specified type. 294More than one type may be specified in a comma separated list. 295The list of filesystem types can be prefixed with 296.Dq no 297to specify the filesystem types for which action should 298.Em not 299be taken. 300For example, the 301.Nm 302command: 303.Bd -literal -offset indent 304mount -a -t nonfs,mfs 305.Ed 306.Pp 307mounts all filesystems except those of type 308.Tn NFS 309and 310.Tn MFS . 311.Pp 312If the type is not the internally known type, 313.Cm ufs , 314.Nm 315will attempt to execute a program in 316.Pa /sbin/mount_ Ns Sy XXX 317where 318.Sy XXX 319is replaced by the type name. 320For example, nfs filesystems are mounted by the program 321.Pa /sbin/mount_nfs . 322.Pp 323Most filesystems will be dynamically loaded by their 324.Nm 325programs 326if not already present in the kernel, using the 327.Xr vfsload 3 328subroutine. 329Because this mechanism requires writable temporary space, 330the filesystem type containing 331.Pa /tmp 332must be compiled into the kernel, and the filesystems containing 333.Pa /tmp 334and 335.Pa /usr/bin/ld 336must be listed in 337.Pa /etc/fstab 338before any filesystems which might be dynamically loaded. 339.It Fl u 340The 341.Fl u 342flag indicates that the status of an already mounted file 343system should be changed. 344Any of the options discussed above (the 345.Fl o 346option) 347may be changed; 348also a file system can be changed from read-only to read-write 349or vice versa. 350An attempt to change from read-write to read-only will fail if any 351files on the filesystem are currently open for writing unless the 352.Fl f 353flag is also specified. 354The set of options is determined by applying the options specified 355in the argument to 356.Fl o 357and finally applying the 358.Fl r 359or 360.Fl w 361option. 362.It Fl v 363Verbose mode. 364.It Fl w 365The file system object is to be read and write. 366.El 367.Sh ENVIRONMENT 368.Bl -tag -width PATH_FSTAB 369.It Pa PATH_FSTAB 370If the environment variable 371.Pa PATH_FSTAB 372is set all operations are performed against the specified file. 373.El 374.Sh FILES 375.Bl -tag -width /etc/fstab -compact 376.It Pa /etc/fstab 377file system table 378.El 379.Sh DIAGNOSTICS 380Various, most of them are self-explanatory. 381.Pp 382.Dl XXXXX filesystem is not available 383.Pp 384The kernel does not support the respective filesystem type. 385Note that 386support for a particular filesystem might be provided either on a static 387(kernel compile-time), or dynamic basis (loaded as a kernel module by 388.Xr kldload 8 ) . 389Normally, 390.Nm 391or its subprocesses attempt to dynamically load a filesystem module if 392it has not been configured statically, using 393.Xr vfsload 3 . 394In this case, the above error message can also mean that you did not 395have permission to load the module. 396.Sh SEE ALSO 397.Xr df 1 , 398.Xr lsvfs 1 , 399.Xr mount 2 , 400.Xr vfsload 3 , 401.Xr devtab 5 , 402.Xr fstab 5 , 403.Xr UFS 5 , 404.Xr automount 8 , 405.Xr automountd 8 , 406.Xr autounmountd 8 , 407.Xr kldload 8 , 408.Xr mount_cd9660 8 , 409.Xr mount_devfs 8 , 410.Xr mount_ext2fs 8 , 411.Xr mount_hammer 8 , 412.Xr mount_hpfs 8 , 413.Xr mount_mfs 8 , 414.Xr mount_msdos 8 , 415.Xr mount_nfs 8 , 416.Xr mount_ntfs 8 , 417.Xr mount_null 8 , 418.Xr mount_procfs 8 , 419.Xr mount_smbfs 8 , 420.Xr mount_std 8 , 421.Xr mount_tmpfs 8 , 422.Xr mount_udf 8 , 423.Xr sysctl 8 , 424.Xr umount 8 425.Sh HISTORY 426A 427.Nm 428utility appeared in 429.At v1 . 430.Sh CAVEATS 431After a successful 432.Nm , 433the permissions on the original mount point determine if 434.Pa ..\& 435is accessible from the mounted file system. 436The minimum permissions for 437the mount point for traversal across the mount point in both 438directions to be possible for all users is 0111 (execute for all). 439.Sh BUGS 440It is possible for a corrupted file system to cause a crash. 441