Linux and Unix fsck command
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About fsck
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Check and repair a Linux file system.
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 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 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- |
| -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. Note that fsck is not designed to pass arbitrarily complicated options to filesystem-specific checkers. If |
Options to different filesystem-specific fsck's are not standardized. If in doubt, 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 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. |
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.