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Quick links About fsck
Syntax
Examples
Related commands
Linux / Unix main page
About fsck
Check and repair a Linux file system.
Syntax
fsck [ -sAVRTNP ] [ -C [ fd ] ] [ -t fstype ] [filesys
... ] [--] [ fs-specific-options ]
| -s |
Serialize fsck operations. This
is a good idea if you are checking multiple filesystems and
the checkers are in an interactive mode. (Note: e2fsck(8)
runs in an interactive mode by default. To make e2fsck(8)
run in a non-interactive mode, you must either specify the
-p or -a option, if you wish for errors to be corrected
automatically, or the -n option if you do not.) |
| -t fstype |
Specifies the type(s) of file
system to be checked. When the -A flag is specified, only
filesystems that match fslist are checked. The fslist
parameter is a comma-separated list of filesystems and
options specifiers. All of the filesystems in this
comma-separated list may be prefixed by a negation operator
'no' or '!', which requests
that only those filesystems not listed in fslist will be
checked. If all of the filesystems in fslist are not
prefixed by a negation operator, then only those filesystems
listed in fslist will be checked.Options specifiers may
be included in the comma separated fslist. They must have
the format opts=fs-option. If an options specifier is
present, then only filesystems which contain fs-option in
their mount options field of /etc/fstab will be checked. If
the options specifier is prefixed by a negation operator,
then only those filesystems that do not have fs-option in
their mount options field of /etc/fstab will be checked.
For example, if opts=ro appears in fslist, then only
filesystems listed in /etc/fstab with the ro option will be
checked.
For compatibility with Mandrake distributions whose boot
scripts depend upon an unauthorized UI change to the fsck
program, if a filesystem type of loop is found in fslist, it
is treated as if opts=loop were specified as an argument to
the -t option.
Normally, the filesystem type is deduced by searching for
filesys in the /etc/fstab file and using the corresponding
entry. If the type can not be deduced, and there is only a
single filesystem given as an argument to the -t option,
fsck will use the specified filesystem type. If this type is
not available, then the default file system type (currently
ext2) is used. |
| -A |
Walk through the /etc/fstab file
and try to check all file systems in one run. This option is
typically used from
the /etc/rc system initalization file, instead of multiple
commands for checking a single file system.The root
filesystem will be checked first unless the -P option is
specified (see below). After that, filesystems
will be checked in the order specified by the fs_passno (the
sixth) field in the /etc/fstab file. Filesystems with a
fs_passno value of 0 are skipped and are not checked at all.
Filesystems with a fs_passno value of greater than zero will
be checked in order, with filesystems with the lowest
fs_passno number being checked first. If there are multiple
filesystems with the same pass number, fsck will attempt to
check them in parallel, although it will avoid running
multiple filesystem checks on the same physical disk.
Hence, a very common configuration in /etc/fstab files is
to set the root filesystem to have a fs_passno value of 1
and to set all filesystems to have a fs_passno value of 2.
This will allow fsck to automatically run filesystem
checkers in parallel if it is advantageous to do so. System
administrators might choose not to use this configu-
ration if they need to avoid multiple filesystem checks
running in parallel for some reason --- for example, if the
machine in question is short on memory so that excessive
paging is a concern. |
| -C [ fd ] |
Display completion/progress bars
for those filesystem checkers (currently only for ext2 and
ext3) which support them. Fsck will manage the filesystem
checkers so that only one of them will display a progress
bar at a time. GUI front-ends may specify a file descriptor
fd, in which case the progress bar information will be sent
that file descriptor. |
| -N |
Don't execute, just show what
would be done. |
| -P |
When the -A flag is set, check
the root filesystem in parallel with the other filesystems.
This is not the safest thing in the world to do, since if
the root filesystem is in doubt things like the e2fsck(8)
executable might be corrupted! This option is mainly
provided for those sysadmins who don't want to repartition
the root filesystem to be small and compact (which is really
the right solution). |
| -R |
When checking all file systems
with the -A flag, skip the root file system (in case it's
already mounted read-write). |
| -T |
Don't show the title on startup. |
| -V |
Produce verbose output,
including all file system-specific commands that are
executed. |
| fs-specific-options |
Options which are not understood
by fsck are passed to the filesystem-specific checker. These
arguments must not take arguments, as there is no way for
fsck to be able to properly guess which arguments take
options and which don't. Options and arguments which
follow the -- are treated as file system-specific options to
be passed to the file system-specific checker.
Please note that fsck is not designed to pass arbitrarily
complicated options to filesystem-specific checkers. If
you're doing something complicated, please just execute the
filesystem-specific checker directly. If you pass fsck some
horribly complicated option and arguments, and it doesn't do
what you expect, don't bother reporting it as a bug. You're
almost certainly doing something that you shouldn't be doing
with fsck. |
Options to different filesystem-specific fsck's
are not standardized. If in doubt, please consult the man pages
of the filesystem-specific checker. Although not guaranteed, the
following options are supported by most file system checkers:
| -a |
Automatically repair the file
system without any questions (use this option with caution).
Note that e2fsck(8) supports -a for backwards compatibility
only. This option is mapped to e2fsck's -p option which is
safe to use,
unlike the -a option that some file system checkers support. |
| -n |
For some filesystem-specific
checkers, the -n option will cause the fs-specific fsck to
avoid attempting to repair any problems, but simply report
such problems to stdout. This is however not true for all
filesystem-specific checkers. In particular,
fsck.reiserfs(8) will not report any corruption if given
this option. fsck.minix(8) does not support the -n option at
all. |
| -r |
Interactively repair the
filesystem (ask for confirmations). Note: It is generally a
bad idea to use this option if multiple fsck's are being run
in parallel. Also note that this is e2fsck's default
behavior; it supports this option for backwards
compatibility reasons only. |
| -y |
For some filesystem-specific
checkers, the -y option will cause the fs-specific fsck to
always attempt to fix any detected filesystem corruption
automatically. Sometimes an expert may be able to do better
driving the fsck manually. Note that not all
filesystem-specific checkers implement this option. In
particular fsck.minix(8) and fsck.cramfs(8) does not support
the -y option as of this writing. |
Examples
fsck -A
Run through the /etc/fstab file and try to check
all file systems in one run.
fsck -t ext2 /dev/fd0
Check the ext2 filesystem on the floppy diskette
drive. In order for this example to work you must have file
system unmounted using the umount command.
Related commands
mkfs
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