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MOUNT(8)		FreeBSD System Manager's Manual 	      MOUNT(8)

NAME
     mount - mount file systems

SYNOPSIS
     mount [-adfpruvw] [-t ufs | lfs | external_type]
     mount [-dfpruvw] special | node
     mount [-dfpruvw] [-o options] [-t ufs | lfs | external_type] special node

DESCRIPTION
     The mount command calls the mount(2) system call to prepare and graft a
     special device or the remote node (rhost:path) on to the file system tree
     at the point node. If either special or node are not provided, the appro­
     priate information is taken from the fstab(5) file.

     The system maintains a list of currently mounted file systems.  If no ar­
     guments are given to mount, this list is printed.

     The options are as follows:

     -a      All the filesystems described in fstab(5) are mounted.  Excep­
	     tions are those marked as ``noauto'', excluded by the -t flag
	     (see below), or if they are already mounted (except the root
	     filesystem which is always remounted to preserve traditional sin­
	     gle user mode behavior).

     -d      Causes everything to be done except for the actual system call.
	     This option is useful in conjunction with the -v flag to deter­
	     mine what the mount command is trying to do.

     -f      Forces the revocation of write access when trying to downgrade a
	     filesystem mount status from read-write to read-only.  Also
	     forces the R/W mount of an unclean filesystem (dangerous; use
	     with caution).

     -o      Options are specified with a -o flag followed by a comma separat­
	     ed string of options.  In case of conflicting options being spec­
	     ified, the rightmost option takes effect.	The following options
	     are available:

	     async   All I/O to the file system should be done asynchronously.
		     This is a dangerous flag to set, and should not be used
		     unless you are prepared to recreate the file system
		     should your system crash.

	     current
		     When used with the -u flag, this is the same as specify­
		     ing the options currently in effect for the mounted
		     filesystem.

	     force   The same as -f; forces the revocation of write access
		     when trying to downgrade a filesystem mount status from
		     read-write to read-only.  Also forces the R/W mount of an
		     unclean filesystem (dangerous; use with caution).

	     fstab   When used with the -u flag, this is the same as specify­
		     ing all the options listed in the fstab(5) file for the
		     filesystem.

	     noasync
		     Metadata I/O should be done synchronously, while data I/O
		     should be done asynchronously.  This is the default.

	     noatime
		     Do not update the file access time when reading from a
		     file.  This option is useful on filesystems where there
		     are large numbers of files and performance is more criti­
		     cal than updating the file access time (which is rarely
		     ever important). This option is currently only supported
		     on local filesystems.

	     noauto  This filesystem should be skipped when mount is run with
		     the -a flag.

	     noclusterr
		     Disable read clustering.

	     noclusterw
		     Disable write clustering.

	     nodev   Do not interpret character or block special devices on
		     the file system.  This option is useful for a server that
		     has file systems containing special devices for architec­
		     tures other than its own.

	     noexec  Do not allow execution of any binaries on the mounted
		     file system.  This option is useful for a server that has
		     file systems containing binaries for architectures other
		     than its own.

	     nosuid  Do not allow set-user-identifier or set-group-identifier
		     bits to take effect.  Note: this option is worthless if a
		     public available suid or sgid wrapper like suidperl(1) is
		     installed on your system.

	     nosymfollow
		     Do not follow symlinks on the mounted file system.

	     rdonly  The same as -r; mount the file system read-only (even the
		     super-user may not write it).

	     sync    All I/O to the file system should be done synchronously.

	     suiddir
		     A directory on the mounted filesystem will respond to the
		     SUID bit being set, by setting the owner of any new files
		     to be the same as the owner of the directory.  New direc­
		     tories will inherit the bit from their parents.  Execute
		     bits are removed from the file, and it will not be given
		     to root.

		     This feature is designed for use on fileservers serving
		     PC users via ftp, SAMBA, or netatalk.  It provides secu­
		     rity holes for shell users and as such should not be used
		     on shell machines, especially on home directories.  This
		     option requires the SUIDDIR option in the kernel to work.
		     Only UFS filesystems support this option.	See chmod(2)
		     for more information.

	     update  The same as -u; indicate that the status of an already
		     mounted file system should be changed.

	     union   Causes the namespace at the mount point to appear as the
		     union of the mounted filesystem root and the existing di­
		     rectory.  Lookups will be done in the mounted filesystem
		     first.  If those operations fail due to a non-existent
		     file the underlying directory is then accessed.  All cre­
		     ates are done in the mounted filesystem.

	     Any additional options specific to a filesystem type that is not
	     one of the internally known types (see the -t option) may be
	     passed as a comma separated list; these options are distinguished
	     by a leading ``-'' (dash).  Options that take a value are speci­
	     fied using the syntax -option=value.  For example, the mount com­
	     mand:

		   mount -t mfs -o nosuid,-N,-s=4000 /dev/dk0b /tmp

	     causes mount to execute the equivalent of:

		   /sbin/mount_mfs -o nosuid -N -s 4000 /dev/dk0b /tmp

	     Additional options specific to filesystem types which are not in­
	     ternally known (see the description of the -t option below) may
	     be described in the manual pages for the associated
	     /sbin/mount_XXX utilities.

     -p      Print mount information in fstab format.  Implies also the -v op­
	     tion.

     -r      The file system is to be mounted read-only.  Mount the file sys­
	     tem read-only (even the super-user may not write it).  The same
	     as the ``rdonly'' argument to the -o option.

     -t ufs | lfs | external type
	     The argument following the -t is used to indicate the file system
	     type.  The type ufs is the default.  The -t option can be used to
	     indicate that the actions should only be taken on filesystems of
	     the specified type.  More than one type may be specified in a
	     comma separated list.  The list of filesystem types can be pre­
	     fixed with ``no'' to specify the filesystem types for which ac­
	     tion should not be taken.	For example, the mount command:

		   mount -a -t nonfs,mfs

	     mounts all filesystems except those of type NFS and MFS.

	     If the type is not one of the internally known types, mount will
	     attempt to execute a program in /sbin/mount_XXX where XXX is re­
	     placed by the type name.  For example, nfs filesystems are mount­
	     ed by the program /sbin/mount_nfs.

	     Most filesystems will be dynamically loaded by their mount pro­
	     grams if not already present in the kernel, using the vfsload(3)
	     subroutine.  Because this mechanism requires writable temporary
	     space, the filesystem type containing /tmp must be compiled into
	     the kernel, and the filesystems containing /tmp and /usr/bin/ld
	     must be listed in /etc/fstab before any filesystems which might
	     be dynamically loaded.

     -u      The -u flag indicates that the status of an already mounted file
	     system should be changed.	Any of the options discussed above
	     (the -o option) may be changed; also a file system can be changed
	     from read-only to read-write or vice versa.  An attempt to change
	     from read-write to read-only will fail if any files on the
	     filesystem are currently open for writing unless the -f flag is
	     also specified.  The set of options is determined by applying the
	     options specified in the argument to -o and finally applying the
	     -r or -w option.

     -v      Verbose mode.

     -w      The file system object is to be read and write.

DIAGNOSTICS
     Various, most of them are self-explanatory.

	   XXXXX filesystem is not available

     The kernel doesn't support the respective filesystem type.  Note that
     support for a particular filesystem might be provided either on a static
     (kernel compile-time), or dynamic basis (loaded as a kernel module by
     kldload(8)).  Normally, mount or its subprocesses attempt to dynamically
     load a filesystem module if it hasn't been configured statically, using
     vfsload(3).  In this case, the above error message can also mean that you
     didn't have permission to load the module.

FILES
     /etc/fstab  file system table

SEE ALSO
     mount(2),	vfsload(3),  fstab(5),	kldload(8),  mount_cd9660(8),
     mount_devfs(8),  mount_fdesc(8),  mount_kernfs(8),  mount_mfs(8),
     mount_msdos(8),  mount_nfs(8),  mount_null(8),  mount_portal(8),
     mount_procfs(8),  mount_umap(8),  mount_union(8),	umount(8)

BUGS
     It is possible for a corrupted file system to cause a crash.

CAVEATS
     After a successful mount, the permissions on the original mount point de­
     termine if .. is accessible from the mounted file system.	The minimum
     permissions for the mount point for traversal across the mount point in
     both directions to be possible for all users is 0111 (execute for all).

HISTORY
     A mount command appeared in Version 1 AT&T UNIX.

4th Berkeley Distribution	 June 16, 1994				     4

NAME | SYNOPSIS | DESCRIPTION | DIAGNOSTICS | FILES | SEE ALSO | BUGS | CAVEATS | HISTORY

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