Linux Pocket Guide, 2nd Edition

Name

fsck — stdin  stdout  - file  -- opt  --help  --version

Synopsis

fsck [options] [devices]

The fsck (filesystem check) command validates a Linux disk partition and, if requested, repairs errors found on it. fsck is run automatically when your system boots; however, you can run it manually if you like. In general, unmount a device before checking it, so no other programs are operating on it at the same time:

# umount /dev/sda10
# fsck -f /dev/sda10
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/home: 172/1281696 files (11.6% non-contiguous), ...

fsck is a frontend for a set of filesystem-checking programs found in /sbin, with names beginning “fsck”. Only certain types of filesystems are supported; you can list them with the command:

$ ls /sbin/fsck.* | cut -d. -f2

Useful options

-A	Check all disks listed in /etc/fstab, in order.
-N	Print a description of the checking that would be done, but exit without performing any checking.
-r	Fix errors interactively, prompting before each fix.
-a	Fix errors automatically (use only if you really know what you’re doing; if not, you can seriously mess up a filesystem).