fsck - Check and Repair a Linux Filesystem

FSCK(8) System Administration FSCK(8) NAME fsck - check and repair a Linux filesystem SYNOPSIS fsck [-lsAVRTMNP] [-r [fd]] [-C [fd]] [-t fstype] [filesystem...] [--] [fs-specific-options] DESCRIPTION fsck is used to check and optionally repair one or more Linux filesystems. filesystem can be a device name (e.g., /dev/hdc1, /dev/sdb2), a mount point (e.g., /, /usr, /home), or a filesystem label or UUID specifier (e.g., UUID=8868abf6-88c5-4a83-98b8-bfc24057f7bd or LABEL=root). Normally, the fsck program will try to handle filesystems on different physical disk drives in parallel to reduce the total amount of time needed to check all of them. If no filesystems are specified on the command line, and the -A option is not specified, fsck will default to checking filesystems in /etc/fstab serially. This is equivalent to the -As options. The exit status returned by fsck is the sum of the following conditions: 0 No errors 1 Filesystem errors corrected 2 System should be rebooted 4 Filesystem errors left uncorrected 8 Operational error 16 Usage or syntax error 32 Checking canceled by user request 128 Shared-library error The exit status returned when multiple filesystems are checked is the bit-wise OR of the exit statuses for each filesystem that is checked. In actuality, fsck is simply a front-end for the various filesystem checkers (fsck.fstype) available under Linux. The filesystem-specific checker is searched for in the PATH environment variable. If the PATH is undefined then fallback to /sbin. Please see the filesystem-specific checker manual pages for further details. OPTIONS -l Create an exclusive flock(2) lock file (/run/fsck/<diskname>.lock) for whole-disk device. This option can be used with one device only (this means that -A and -l are mutually exclusive). This option is recommended when more fsck instances are executed in the same time. The option is ignored when used for multiple devices or for non-rotating disks. fsck does not lock underlying devices when executed to check stacked devices (e.g. MD or DM) - this feature is not implemented yet. -r [fd] Report certain statistics for each fsck when it completes. These statistics include the exit status, the maximum run set size (in kilobytes), the elapsed all-clock time and the user and system CPU time used by the fsck run. For example: /dev/sda1: status 0, rss 92828, real 4.002804, user 2.677592, sys 0.86186 GUI front-ends may specify a file descriptor fd, in which case the progress bar information will be sent to that file descriptor in a machine parsable format. For example: /dev/sda1 0 92828 4.002804 2.677592 0.86186 -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 fslist Specifies the type(s) of filesystem 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

This document describes the fsck command, which is used to check and repair Linux filesystems. It details the command's syntax, options (such as -l for exclusive locking, -r for reporting statistics, -s for serializing operations, and -t for specifying filesystem types), exit status codes, and its role as a front-end for filesystem-specific checkers. The document also explains how fsck handles multiple filesystems and provides examples of its usage.