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

     mount -- mount file systems

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

     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 ap-
     propriate 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 filesys-
	     tem which is always remounted to preserve traditional single 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 sepa-
	     rated string of options.  In case of conflicting options being
	     specified,	the rightmost option takes effect.  The	following op-
	     tions 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.

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

	     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

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

		     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.

		     Disable read clustering.

		     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.

		     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.

		     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 specified
	     using the syntax -option=value.  For example, the mount command:

		   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(5) format.  Implies also the -v

     -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 action
	     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
	     mounted 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.

     Various, most of them are self-explanatory.

	   XXXXX filesystem is not available

     The kernel	does not 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 has	not been configured statically,	using
     vfsload(3).  In this case,	the above error	message	can also mean that you
     did not have permission to	load the module.

     /etc/fstab	 file system table

     mount(2), vfsload(3), fstab(5), kldload(8), mount_cd9660(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)

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

     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).

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

BSD				 June 16, 1994				   BSD


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