MOUNT(8) | System Manager's Manual | MOUNT(8) |
mount
—
mount |
[-Aadfruvw ] [-t
type] |
mount |
[-dfruvw ] {special |
node} |
mount |
[-dfruvw ] [-o
options] [-t
type] special node |
mount
command invokes a file system-specific program
to prepare and graft the special device on to the file
system tree at the point node, or to update options for
an already-mounted file system.
These programs are named “mount_<fstype>” where “<fstype>” refers to the file system-specific type; for example for NFS the mount program is called mount_nfs(8).
The node argument is always interpreted as a directory in the name space of currently mounted file systems. The special argument is interpreted in different ways by the programs that handle different file system types; for example, mount_ffs(8) interprets it as a device node, mount_null(8) interprets it as a directory name, mount_nfs(8) interprets it as reference to a remote host and a directory on that host, and mount_tmpfs(8) ignores it.
The system maintains a list of currently mounted file systems.
This list is printed if mount
is invoked with no
arguments, and with no options that require some other behaviour.
If exactly one of special or
node is provided, then the missing information
(including the file system type) is taken from the
fstab(5) file. The provided
argument is looked up first in the “fs_file”, then in the
“fs_spec” column. If the matching entry in
fstab(5) has the string
“from_mount
” as its
“fs_spec” field, the device or remote file system already
mounted at the location specified by “fs_spec” will be
used.
If both special and
node are provided, then
fstab(5) is not used. In this
case, if the file system type is not specified via the
-t
flag, then mount
may
determine the type from the disk label (see
disklabel(8)). In addition,
if special contains a colon
(‘:
’) or at sign
(‘@
’), then the
nfs
type is inferred, but this behaviour is
deprecated, and will be removed in a future version of
mount
.
In NetBSD, the file-system mounting policy is dictated by the running security models. The default security model may allow unprivileged mounting; see secmodel_suser(9) and secmodel_extensions(9) for details.
The options are as follows:
-A
mount
to try to mount all of the file
systems listed in the
fstab(5) file except those
for which the “noauto” option is specified.-a
-A
flag, except that if a file
system (other than the root file system) appears to be already mounted,
mount
will not try to mount it again.
mount
assumes that a file system is already
mounted if a file system with the same type is mounted on the given mount
point. More stringent checks are not possible because some file system
types report strange values for the mounted-from device for mounted file
systems.-d
-v
flag to determine what the
mount
command is trying to do.-f
-o
-o
flag followed by a
comma separated string of options. The following options are available:
async
noasync
async
mode.automounted
discard
EXPERIMENTAL - negatively influences
filesystem performance by increasing fragmentation, causes free
block map inconsistency on unclean shutdown, and is incompatible
with log
. If log
option is also used, discard
is
automatically disabled.
extattr
force
-f
; forces the revocation of write
access when trying to downgrade a file system mount status from
read-write to read-only.getargs
MNT_IGNORE
flag, causes the
mount point to be excluded from the list of file systems shown by
default with df(1).noatime
noauto
-a
flag.nocoredump
nodev
nodevmtime
noexec
nosuid
port
rdonly
-r
; mount the file system
read-only (even the super-user may not write it).reload
rump
-t
flag and respective rump_type manual page
for more information.log
WAPBL
option
to be enabled in the running kernel. See
wapbl(4) for more
information. This option requires the “UFS2” (level 4)
superblock layout, which is the default for newly created FFSv1 and
FFSv2 file systems. To update an old file system with an earlier
superblock format, use the -c
option of
fsck_ffs(8).
log
cannot be used together with
discard
.
A file system mounted with log
can
be mounted also with async
, but such
filesystem behaves the same as if async
was
not specified - meta-data writes use the log, hence its integrity is
still guaranteed.
symperm
sync
nosync
sync
mode.union
Note that the union
option can be
applied to any type of file system, and is fundamentally different
from
mount_union(8),
which is a particular type of file system. Also note that the
union
option affects the file system name
space only at the mount point itself; it does not apply recursively
to subdirectories.
update
-u
; indicate that the status of an
already mounted file system should be changed.Any additional options specific to a given file system type
(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=32m swap /tmp
causes mount
to execute the equivalent
of:
/sbin/mount_mfs -o nosuid -N -s 32m swap /tmp
-r
-o
option.-t
type-t
is used to indicate
the file system type. The type ffs 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 prefixed with “no” to specify the file
system types for which action should not be taken. For
example, the mount
command:
mount -a -t nonfs,mfs
mounts all file systems except those of type NFS and MFS.
mount
will attempt to execute a
program in /sbin/mount_XXX
where XXX is replaced by the type name. For example,
nfs file systems are mounted by the program
/sbin/mount_nfs.
-u
-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 first extracting the options for the file system from the
fstab(5) file, then applying
any options specified by the -o
argument, and
finally applying the -r
or
-w
option.-v
-w
The options specific to the various file system types are described in the manual pages for those file systems' “mount_<fstype>” commands; for instance, the options specific to Berkeley Fast File System (FFS) are described in the mount_ffs(8) manual page.
The particular type of file system in each partition of a disk can be found by examining the disk label with the disklabel(8) command.
The “noauto” directive in /etc/fstab can be used to make it easy to manually mount and unmount removable media using just the mountpoint filename, with an entry like this:
/dev/cd0a /cdrom cd9660 ro,noauto 0
0
That would allow a simple command like “mount /cdrom” or “umount /cdrom” for media using the ISO-9660 file system format in the first CD-ROM drive.
The error “Operation not permitted” may indicate that the mount options include privileged options and/or do not include options that exclude privileged options. One should try using at least “nodev” and “nosuid” in such cases:
mount -t cd9660 -o nodev,nosuid /dev/cd0a /mnt
mount
command appeared in
Version 1 AT&T UNIX.
January 8, 2018 | NetBSD 9.4 |