{ "mode": "man", "parameter": "fsck", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/fsck/8/json", "generated": "2026-05-30T07:08:38Z", "synopsis": "fsck [-lsAVRTMNP] [-r [fd]] [-C [fd]] [-t fstype] [filesystem...] [--] [fs-specific-options]", "sections": { "NAME": { "content": "fsck - check and repair a Linux filesystem\n", "subsections": [] }, "SYNOPSIS": { "content": "fsck [-lsAVRTMNP] [-r [fd]] [-C [fd]] [-t fstype] [filesystem...] [--] [fs-specific-options]\n", "subsections": [] }, "DESCRIPTION": { "content": "fsck is used to check and optionally repair one or more Linux filesystems. filesystem can be\na device name (e.g., /dev/hdc1, /dev/sdb2), a mount point (e.g., /, /usr, /home), or an\nfilesystem label or UUID specifier (e.g., UUID=8868abf6-88c5-4a83-98b8-bfc24057f7bd or\nLABEL=root). Normally, the fsck program will try to handle filesystems on different physical\ndisk drives in parallel to reduce the total amount of time needed to check all of them.\n\nIf no filesystems are specified on the command line, and the -A option is not specified, fsck\nwill default to checking filesystems in /etc/fstab serially. This is equivalent to the -As\noptions.\n\nThe exit status returned by fsck is the sum of the following conditions:\n\n0\nNo errors\n\n1\nFilesystem errors corrected\n\n2\nSystem should be rebooted\n\n4\nFilesystem errors left uncorrected\n\n8\nOperational error\n\n16\nUsage or syntax error\n\n32\nChecking canceled by user request\n", "subsections": [ { "name": "128", "content": "Shared-library error\n\nThe exit status returned when multiple filesystems are checked is the bit-wise OR of the exit\nstatuses for each filesystem that is checked.\n\nIn actuality, fsck is simply a front-end for the various filesystem checkers (fsck.fstype)\navailable under Linux. The filesystem-specific checker is searched for in the PATH\nenvironment variable. If the PATH is undefined then fallback to /sbin.\n\nPlease see the filesystem-specific checker manual pages for further details.\n" } ] }, "OPTIONS": { "content": "", "subsections": [ { "name": "-l", "content": "Create an exclusive flock(2) lock file (/run/fsck/.lock) for whole-disk device.\nThis option can be used with one device only (this means that -A and -l are mutually\nexclusive). This option is recommended when more fsck instances are executed in the same\ntime. The option is ignored when used for multiple devices or for non-rotating disks.\nfsck does not lock underlying devices when executed to check stacked devices (e.g. MD or\nDM) - this feature is not implemented yet.\n", "flag": "-l" }, { "name": "-r", "content": "Report certain statistics for each fsck when it completes. These statistics include the\nexit status, the maximum run set size (in kilobytes), the elapsed all-clock time and the\nuser and system CPU time used by the fsck run. For example:\n\n/dev/sda1: status 0, rss 92828, real 4.002804, user 2.677592, sys 0.86186\n\nGUI front-ends may specify a file descriptor fd, in which case the progress bar\ninformation will be sent to that file descriptor in a machine parsable format. For\nexample:\n\n/dev/sda1 0 92828 4.002804 2.677592 0.86186\n", "flag": "-r" }, { "name": "-s", "content": "Serialize fsck operations. This is a good idea if you are checking multiple filesystems\nand the checkers are in an interactive mode. (Note: e2fsck(8) runs in an interactive mode\nby default. To make e2fsck(8) run in a non-interactive mode, you must either specify the\n-p or -a option, if you wish for errors to be corrected automatically, or the -n option\nif you do not.)\n", "flag": "-s" }, { "name": "-t", "content": "Specifies the type(s) of filesystem to be checked. When the -A flag is specified, only\nfilesystems that match fslist are checked. The fslist parameter is a comma-separated list\nof filesystems and options specifiers. All of the filesystems in this comma-separated\nlist may be prefixed by a negation operator 'no' or '!', which requests that only those\nfilesystems not listed in fslist will be checked. If none of the filesystems in fslist is\nprefixed by a negation operator, then only those listed filesystems will be checked.\n\nOptions specifiers may be included in the comma-separated fslist. They must have the\nformat opts=fs-option. If an options specifier is present, then only filesystems which\ncontain fs-option in their mount options field of /etc/fstab will be checked. If the\noptions specifier is prefixed by a negation operator, then only those filesystems that do\nnot have fs-option in their mount options field of /etc/fstab will be checked.\n\nFor example, if opts=ro appears in fslist, then only filesystems listed in /etc/fstab\nwith the ro option will be checked.\n\nFor compatibility with Mandrake distributions whose boot scripts depend upon an\nunauthorized UI change to the fsck program, if a filesystem type of loop is found in\nfslist, it is treated as if opts=loop were specified as an argument to the -t option.\n\nNormally, the filesystem type is deduced by searching for filesys in the /etc/fstab file\nand using the corresponding entry. If the type cannot be deduced, and there is only a\nsingle filesystem given as an argument to the -t option, fsck will use the specified\nfilesystem type. If this type is not available, then the default filesystem type\n(currently ext2) is used.\n", "flag": "-t" }, { "name": "-A", "content": "Walk through the /etc/fstab file and try to check all filesystems in one run. This option\nis typically used from the /etc/rc system initialization file, instead of multiple\ncommands for checking a single filesystem.\n\nThe root filesystem will be checked first unless the -P option is specified (see below).\nAfter that, filesystems will be checked in the order specified by the fspassno (the\nsixth) field in the /etc/fstab file. Filesystems with a fspassno value of 0 are skipped\nand are not checked at all. Filesystems with a fspassno value of greater than zero will\nbe checked in order, with filesystems with the lowest fspassno number being checked\nfirst. If there are multiple filesystems with the same pass number, fsck will attempt to\ncheck them in parallel, although it will avoid running multiple filesystem checks on the\nsame physical disk.\n\nfsck does not check stacked devices (RAIDs, dm-crypt, ...) in parallel with any other\ndevice. See below for FSCKFORCEALLPARALLEL setting. The /sys filesystem is used to\ndetermine dependencies between devices.\n\nHence, a very common configuration in /etc/fstab files is to set the root filesystem to\nhave a fspassno value of 1 and to set all other filesystems to have a fspassno value of\n2. This will allow fsck to automatically run filesystem checkers in parallel if it is\nadvantageous to do so. System administrators might choose not to use this configuration\nif they need to avoid multiple filesystem checks running in parallel for some reason -\nfor example, if the machine in question is short on memory so that excessive paging is a\nconcern.\n\nfsck normally does not check whether the device actually exists before calling a\nfilesystem specific checker. Therefore non-existing devices may cause the system to enter\nfilesystem repair mode during boot if the filesystem specific checker returns a fatal\nerror. The /etc/fstab mount option nofail may be used to have fsck skip non-existing\ndevices. fsck also skips non-existing devices that have the special filesystem type auto.\n", "flag": "-A" }, { "name": "-C", "content": "Display completion/progress bars for those filesystem checkers (currently only for\next[234]) which support them. fsck will manage the filesystem checkers so that only one\nof them will display a progress bar at a time. GUI front-ends may specify a file\ndescriptor fd, in which case the progress bar information will be sent to that file\ndescriptor.\n", "flag": "-C" }, { "name": "-M", "content": "Do not check mounted filesystems and return an exit status of 0 for mounted filesystems.\n", "flag": "-M" }, { "name": "-N", "content": "Don’t execute, just show what would be done.\n", "flag": "-N" }, { "name": "-P", "content": "When the -A flag is set, check the root filesystem in parallel with the other\nfilesystems. This is not the safest thing in the world to do, since if the root\nfilesystem is in doubt things like the e2fsck(8) executable might be corrupted! This\noption is mainly provided for those sysadmins who don’t want to repartition the root\nfilesystem to be small and compact (which is really the right solution).\n", "flag": "-P" }, { "name": "-R", "content": "When checking all filesystems with the -A flag, skip the root filesystem. (This is useful\nin case the root filesystem has already been mounted read-write.)\n", "flag": "-R" }, { "name": "-T", "content": "Don’t show the title on startup.\n", "flag": "-T" }, { "name": "-V", "content": "Produce verbose output, including all filesystem-specific commands that are executed.\n\n-?, --help\nDisplay help text and exit.\n", "flag": "-V" }, { "name": "--version", "content": "Display version information and exit.\n", "long": "--version" } ] }, "FILESYSTEM SPECIFIC OPTIONS": { "content": "", "subsections": [ { "name": "Options which are not understood by fsck are passed to the filesystem-specific checker!", "content": "These options must not take arguments, as there is no way for fsck to be able to properly\nguess which options take arguments and which don’t.\n\nOptions and arguments which follow the -- are treated as filesystem-specific options to be\npassed to the filesystem-specific checker.\n\nPlease note that fsck is not designed to pass arbitrarily complicated options to\nfilesystem-specific checkers. If you’re doing something complicated, please just execute the\nfilesystem-specific checker directly. If you pass fsck some horribly complicated options and\narguments, and it doesn’t do what you expect, don’’t bother reporting it as a bug. You’re\nalmost certainly doing something that you shouldn’t be doing with fsck. Options to different\nfilesystem-specific fsck’s are not standardized.\n" } ] }, "ENVIRONMENT": { "content": "The fsck program’s behavior is affected by the following environment variables:\n\nFSCKFORCEALLPARALLEL\nIf this environment variable is set, fsck will attempt to check all of the specified\nfilesystems in parallel, regardless of whether the filesystems appear to be on the same\ndevice. (This is useful for RAID systems or high-end storage systems such as those sold\nby companies such as IBM or EMC.) Note that the fspassno value is still used.\n\nFSCKMAXINST\nThis environment variable will limit the maximum number of filesystem checkers that can\nbe running at one time. This allows configurations which have a large number of disks to\navoid fsck starting too many filesystem checkers at once, which might overload CPU and\nmemory resources available on the system. If this value is zero, then an unlimited number\nof processes can be spawned. This is currently the default, but future versions of fsck\nmay attempt to automatically determine how many filesystem checks can be run based on\ngathering accounting data from the operating system.\n\nPATH\nThe PATH environment variable is used to find filesystem checkers.\n\nFSTABFILE\nThis environment variable allows the system administrator to override the standard\nlocation of the /etc/fstab file. It is also useful for developers who are testing fsck.\n\nLIBBLKIDDEBUG=all\nenables libblkid debug output.\n\nLIBMOUNTDEBUG=all\nenables libmount debug output.\n", "subsections": [] }, "FILES": { "content": "/etc/fstab\n", "subsections": [] }, "AUTHORS": { "content": "Theodore Ts’o >, Karel Zak \n", "subsections": [] }, "SEE ALSO": { "content": "fstab(5), mkfs(8), fsck.ext2(8) or fsck.ext3(8) or e2fsck(8), fsck.cramfs(8), fsck.jfs(8),\nfsck.nfs(8), fsck.minix(8), fsck.msdos(8), fsck.vfat(8), fsck.xfs(8), reiserfsck(8)\n", "subsections": [] }, "REPORTING BUGS": { "content": "For bug reports, use the issue tracker at https://github.com/karelzak/util-linux/issues.\n", "subsections": [] }, "AVAILABILITY": { "content": "The fsck command is part of the util-linux package which can be downloaded from Linux Kernel\nArchive .\n\n\n\nutil-linux 2.37.2 2021-07-20 FSCK(8)", "subsections": [] } }, "summary": "fsck - check and repair a Linux filesystem", "flags": [ { "flag": "-l", "long": null, "arg": null, "description": "Create an exclusive flock(2) lock file (/run/fsck/.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." }, { "flag": "-r", "long": null, "arg": null, "description": "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" }, { "flag": "-s", "long": null, "arg": null, "description": "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.)" }, { "flag": "-t", "long": null, "arg": null, "description": "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 negation operator 'no' or '!', which requests that only those filesystems not listed in fslist will be checked. If none of the filesystems in fslist is prefixed by a negation operator, then only those listed filesystems 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 cannot 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 filesystem type (currently ext2) is used." }, { "flag": "-A", "long": null, "arg": null, "description": "Walk through the /etc/fstab file and try to check all filesystems in one run. This option is typically used from the /etc/rc system initialization file, instead of multiple commands for checking a single filesystem. 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 fspassno (the sixth) field in the /etc/fstab file. Filesystems with a fspassno value of 0 are skipped and are not checked at all. Filesystems with a fspassno value of greater than zero will be checked in order, with filesystems with the lowest fspassno 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. fsck does not check stacked devices (RAIDs, dm-crypt, ...) in parallel with any other device. See below for FSCKFORCEALLPARALLEL setting. The /sys filesystem is used to determine dependencies between devices. Hence, a very common configuration in /etc/fstab files is to set the root filesystem to have a fspassno value of 1 and to set all other filesystems to have a fspassno 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 configuration 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. fsck normally does not check whether the device actually exists before calling a filesystem specific checker. Therefore non-existing devices may cause the system to enter filesystem repair mode during boot if the filesystem specific checker returns a fatal error. The /etc/fstab mount option nofail may be used to have fsck skip non-existing devices. fsck also skips non-existing devices that have the special filesystem type auto." }, { "flag": "-C", "long": null, "arg": null, "description": "Display completion/progress bars for those filesystem checkers (currently only for ext[234]) 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 to that file descriptor." }, { "flag": "-M", "long": null, "arg": null, "description": "Do not check mounted filesystems and return an exit status of 0 for mounted filesystems." }, { "flag": "-N", "long": null, "arg": null, "description": "Don’t execute, just show what would be done." }, { "flag": "-P", "long": null, "arg": null, "description": "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)." }, { "flag": "-R", "long": null, "arg": null, "description": "When checking all filesystems with the -A flag, skip the root filesystem. (This is useful in case the root filesystem has already been mounted read-write.)" }, { "flag": "-T", "long": null, "arg": null, "description": "Don’t show the title on startup." }, { "flag": "-V", "long": null, "arg": null, "description": "Produce verbose output, including all filesystem-specific commands that are executed. -?, --help Display help text and exit." }, { "flag": "", "long": "--version", "arg": null, "description": "Display version information and exit." } ], "examples": [], "see_also": [ { "name": "fstab", "section": "5", "url": "https://www.chedong.com/phpMan.php/man/fstab/5/json" }, { "name": "mkfs", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/mkfs/8/json" }, { "name": "fsck.ext2", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/fsck.ext2/8/json" }, { "name": "fsck.ext3", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/fsck.ext3/8/json" }, { "name": "e2fsck", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/e2fsck/8/json" }, { "name": "fsck.cramfs", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/fsck.cramfs/8/json" }, { "name": "fsck.jfs", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/fsck.jfs/8/json" }, { "name": "fsck.nfs", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/fsck.nfs/8/json" }, { "name": "fsck.minix", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/fsck.minix/8/json" }, { "name": "fsck.msdos", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/fsck.msdos/8/json" }, { "name": "fsck.vfat", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/fsck.vfat/8/json" }, { "name": "fsck.xfs", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/fsck.xfs/8/json" }, { "name": "reiserfsck", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/reiserfsck/8/json" } ] }