The system utility fsck (for "file system check") is a tool for checking the consistency of a file system in the UNIX system and clones thereof.
A journaling filesystem is designed such that tools such as fsck do not need to be run as often.
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 interactively repairing damaged file systems (the user must decide how to fix specific problems), allowing fsck to decide 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 she or he believes there is a problem with the file system.
The term 'fsck' has come into use among UNIX system administrators as a written taboo deformation of 'fuck'.
