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

     mount -- mount file systems

     mount [--libxo] [-adflpruvw] [-F fstab] [-o options]
	   [-t [no]type[,type ...]]
     mount [--libxo] [-dfpruvw]	special	| node
     mount [--libxo] [-dfpruvw]	[-o options] [-t [no]type[,type	...]] special

     The mount utility calls the nmount(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:

	     Generate output via libxo(3) in a selection of different human
	     and machine readable formats.  See	xo_parse_args(3) for details
	     on	command	line arguments.

     -a	     All the file systems described in fstab(5)	are mounted.  Excep-
	     tions are those marked as "noauto", those marked as "late"	(un-
	     less the -l option	was specified),	those excluded by the -t flag
	     (see below), or if	they are already mounted (except the root file
	     system 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	fstab
	     Specify the fstab file to use.

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

     -L	     When used in conjunction with the -a option, mount	only those
	     file systems which	are marked as "late".

     -l	     When used in conjunction with the -a option, also mount those
	     file systems which	are marked as "late".

     -n	     For compatibility with some other implementations,	this flag is
	     currently a no-op.

     -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:

	     acls    Enable POSIX.1e Access Control Lists, or ACLs, which can
		     be	customized via the setfacl(1) and getfacl(1) commands.
		     This flag is mutually exclusive with nfsv4acls flag.

	     async   All I/O to	the file system	should be done asynchronously.
		     This is a dangerous flag to set, since it does not	guar-
		     antee that	the file system	structure on the disk will re-
		     main consistent.  For this	reason,	the async flag should
		     be	used sparingly,	and only when some data	recovery mech-
		     anism is present.

		     This flag indicates that the file system was mounted by
		     automountd(8).  Automounted file systems are automati-
		     cally unmounted by	autounmountd(8).

	     autoro  Mount the file system read-write.	If that	fails with an
		     error that	suggests that the media	could be read-only,
		     then automatically	try to mount the file system read-

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

		     Require that the mount point directory be empty.

	     force   The same as -f; forces the	revocation of write access
		     when trying to downgrade a	file system mount status from
		     read-write	to read-only.  Also forces the R/W mount of an
		     unclean file system (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
		     file system.

	     late    This file system should be	skipped	when mount is run with
		     the -a flag but without the -l flag.

		     Force mount to use	the specified program to mount the
		     file system, instead of calling nmount(2) directly.  For

		     mount -t foofs -o mountprog=/mydir/fooprog	/dev/cd0 /mnt

		     Enable multi-label	Mandatory Access Control, or MAC, on
		     the specified file	system.	 If the	file system supports
		     multilabel	operation, individual labels will be main-
		     tained for	each object in the file	system,	rather than
		     using a single label for all objects.  An alternative to
		     the -l flag in tunefs(8).	See mac(4) for more informa-
		     tion, which cause the multilabel mount flag to be set au-
		     tomatically at mount-time.

		     Enable NFSv4 ACLs,	which can be customized	via the
		     setfacl(1)	and getfacl(1) commands.  This flag is mutu-
		     ally exclusive with acls flag.

		     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 file systems 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 file systems.

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

		     Disable read clustering.

		     Disable write clustering.

		     Do	not mount if the requested mount point is already the
		     root of a mount point.

	     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.  Note: This option was not designed as a
		     security feature and no guarantee is made that it will
		     prevent malicious code execution; for example, it is
		     still possible to execute scripts which reside on a
		     noexec mounted partition.

	     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.	It is set automatically	when
		     the user does not have super-user privileges.

		     Do	not follow symlinks on the mounted file	system.

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

		     Take a snapshot of	the specified filesystem.  When	this
		     option is used, all other options are ignored.  The -u
		     flag is required with this	option.

		     Snapshot files must be created in the file	system that is
		     being snapshotted.	 You may create	up to 20 snapshots per
		     file system.  Active snapshots are	recorded in the	su-
		     perblock, so they persist across unmount and remount op-
		     erations and across system	reboots.  When you are done
		     with a snapshot, it can be	removed	with the rm(1) com-
		     mand.  Snapshots may be removed in	any order, however you
		     may not get back all the space contained in the snapshot
		     as	another	snapshot may claim some	of the blocks that it
		     is	releasing.  Note that the schg flag is set on snap-
		     shots to ensure that not even the root user can write to
		     them.  The	unlink command makes an	exception for snapshot
		     files in that it allows them to be	removed	even though
		     they have the schg	flag set, so it	is not necessary to
		     clear the schg flag before	removing a snapshot file.

		     Once you have taken a snapshot, there are three interest-
		     ing things	that you can do	with it:

		     1.	  Run fsck(8) on the snapshot file.  Assuming that the
			  file system was clean	when it	was mounted, you
			  should always	get a clean (and unchanging) result
			  from running fsck on the snapshot.  This is essen-
			  tially what the background fsck process does.

		     2.	  Run dump(8) on the snapshot.	You will get a dump
			  that is consistent with the file system as of	the
			  timestamp of the snapshot.

		     3.	  Mount	the snapshot as	a frozen image of the file
			  system.  To mount the	snapshot /var/snapshot/snap1:

			  mdconfig -a -t vnode -f /var/snapshot/snap1 -u 4
			  mount	-r /dev/md4 /mnt

			  You can now cruise around your frozen	/var file sys-
			  tem at /mnt.	Everything will	be in the same state
			  that it was at the time the snapshot was taken.  The
			  one exception	is that	any earlier snapshots will ap-
			  pear as zero length files.  When you are done	with
			  the mounted snapshot:

			  umount /mnt
			  mdconfig -d -u 4

		     A directory on the	mounted	file system 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
		     directories will inherit the bit from their parents.  Ex-
		     ecute 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 file systems support this	option.	 See chmod(2)
		     for more information.

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

	     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 file system root and the existing
		     directory.	 Lookups will be done in the mounted file sys-
		     tem first.	 If those operations fail due to a non-exis-
		     tent file the underlying directory	is then	accessed.  All
		     creates are done in the mounted file system.

		     The file system is	untrusted and the kernel should	use
		     more extensive checks on the file-system's	metadata be-
		     fore using	it.  This option is intended to	be used	when
		     mounting file systems from	untrusted media	such as	USB
		     memory sticks or other externally-provided	media.

	     Any additional options specific to	a file system 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).  For example, the	mount command:

		   mount -t cd9660 -o -e /dev/cd0 /cdrom

	     causes mount to execute the equivalent of:

		   /sbin/mount_cd9660 -e /dev/cd0 /cdrom

	     Options that take a value are specified using the -option=value

		   mount -t msdosfs -o -u=fred,-g=wheel	/dev/da0s1 /mnt

	     is	equivalent to

		   /sbin/mount_msdosfs -u fred -g wheel	/dev/da0s1 /mnt

	     Additional	options	specific to file system	types which are	not
	     internally	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 ro argument	to the -o option.

     -t	[no]type[,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 file systems of
	     the specified type.  More than one	type may be specified in a
	     comma separated list.  The	list of	file system types can be pre-
	     fixed with	no to specify the file system types for	which action
	     should not	be taken.  For example,	the mount command:

		   mount -a -t nonfs,nullfs

	     mounts all	file systems except those of type NFS and NULLFS.

	     The default behavior of mount is to pass the -t option directly
	     to	the nmount(2) system call in the fstype	option.

	     However, for the following	file system types: cd9660, mfs,
	     msdosfs, nfs, nullfs, smbfs, udf, and unionfs mount will not call
	     nmount(2) directly	and will instead attempt to execute a program
	     in	/sbin/mount_type where type is replaced	by the file system
	     type name.	 For example, nfs file systems are mounted by the pro-
	     gram /sbin/mount_nfs.

	     Most file systems will be dynamically loaded by the kernel	if not
	     already present, and if the kernel	module is available.

     -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	file
	     system are	currently open for writing unless the -f flag is also
	     specified.	 The set of options is determined by applying the op-
	     tions specified in	the argument to	-o and finally applying	the -r
	     or	-w option.

     -v	     Verbose mode.  If the -v is used alone, show all file systems,
	     including those that were mounted with the	MNT_IGNORE flag	and
	     show additional information about each file system	(including
	     fsid when run by root).

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

     PATH_FSTAB	 If the	environment variable PATH_FSTAB	is set,	all operations
		 are performed against the specified file.  PATH_FSTAB will
		 not be	honored	if the process environment or memory address
		 space is considered "tainted".	 (See issetugid(2) for more

     /etc/fstab	 file system table

     Various, most of them are self-explanatory.

	   XXXXX file system is	not available

     The kernel	does not support the respective	file system type.  Note	that
     support for a particular file system might	be provided either on a	static
     (kernel compile-time), or dynamic basis (loaded as	a kernel module	by

     getfacl(1), setfacl(1), nmount(2),	acl(3),	libxo(3), xo_parse_args(3),
     mac(4), cd9660(5),	devfs(5), ext2fs(5), fstab(5), procfs(5), tmpfs(5),
     automount(8), fstyp(8), kldload(8), mount_cd9660(8), mount_msdosfs(8),
     mount_nfs(8), mount_nullfs(8), mount_smbfs(8), mount_udf(8),
     mount_unionfs(8), umount(8), zfs(8), zpool(8)

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

     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).

     Use of the	mount is preferred over	the use	of the file system specific
     mount_XXX commands.  In particular, mountd(8) gets	a SIGHUP signal	(that
     causes an update of the export list) only when the	file system is mounted
     via mount.

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

FreeBSD	13.0			March 17, 2022			  FreeBSD 13.0


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