Fsck

The system utility fsck (for "file system check" or "file system consistency check") is a tool for checking the consistency of a file system in the Unix system and clones thereof.

Generally, fsck is run automatically at boot time when the system detects that a file system is in an inconsistent state, indicating a non-graceful shutdown, such as a crash or power loss. Typically, fsck utilities provide options for either interactively repairing damaged file systems (the user must decide how to fix specific problems), automatically deciding how to fix specific problems (so the user doesn't have to answer any questions), or reviewing the problems that need to be resolved on a file system without actually fixing them.

Fsck can also be run manually by the system administrator if there is believed to be a problem with the file system. However, running fsck on a mounted file system can potentially cause severe data corruption/loss.

A journaling file system is designed such that tools such as fsck do not need to be run as often. The UFS2 Filesystem in FreeBSD has background fsck, so it is usually not necessary to wait for fsck to finish before accessing the disk.

The Microsoft equivalent programs are scandisk and chkdsk. In DOS, chkdsk was used to check file system integrity, but later versions also featured a tool called scandisk for checking disk surface for bad sectors. Windows 95, Windows 98 and Windows Me featured a version of scandisk which ran natively in the Windows environment. The Windows NT series, including NT 4, Windows 2000, and Windows XP all use a modern, updated version of chkdsk which performs both disk surface and file system scanning, though its disk-surface check is less thorough than scandisk's.

Use as profanity

Before the rise of journaling file systems, it was not uncommon for an improperly shut-down Unix system's file system to develop a corrupted superblock. This possibly serious problem could only be resolved by running fsck, which could take anywhere from a few seconds to hours, depending on the volume's size. Because of the severity of fsck not being able to resolve this error, the terms "fsck" and "fscked" have come into use among Unix system administrators as a minced oath. When one is told "Go fsck yourself!" the meaning implied is to "go away, analyze yourself, and fix your problems", mirroring fsck's primary function.

It is unclear whether this usage was cause or effect, as it has been anecdotally reported that Dennis Ritchie has claimed "The second letter was originally different."

Pronunciation

Like many computer jargon terms without vowels, fsck is essentially unpronounceable in most languages and so people are forced to improvise when speaking it aloud. It can be pronounced "F-S-C-K," "F-S-check," "fisk," "fizik," "fuss-uck," "fizz-uck," "fozz-uck," "F-sick," "F-suck" (associated with how long it takes to run ), "F-sek," or "fusk." Some prefer to just pronounce it as "fuck".

See also

• List of Unix programs
• e2fsprogs, which includes the e2fsck utility standard on many Linux distributions

External links

• man fsck
• Checking and Repairing File system with fsck
• Jargon File entry: fscking
• The many faces of fsck