Filesystem consistency check and interactive repair. Journaling file systems avoid the need to run fsck.
Syntax fsck [options] [filesystem] ... Options -- Pass all subsequent options to filesystem-specific checker. All options that fsck doesn't recognize will also be passed. -r Interactive mode; prompt before making any repairs. -s Serial mode. -t fstype Specify the filesystem type. Do not check filesystems of any other type. -A Check all filesystems listed in /etc/fstab. -N Suppress normal execution; just display what would be done. -R Meaningful only with -A: check all filesystems listed in /etc/fstab except the root filesystem. -T Suppress printing of title. -V Verbose mode. EXIT CODES 1 Errors were found and corrected. 2 Reboot suggested. 4 Errors were found but not corrected. 8 fsck encountered an operational error. 16 fsck was called incorrectly. 128 A shared library error was detected.
The return status is the exit status of the last command executed in consequent-commands, or zero if none were executed.
Dennis Ritchie: “So fsck was originally called something else”
Question: “What was it called?”
Dennis Ritchie: "Well, the second letter was different" ~ Q&A at Usenix
reboot - Reboot the machine
ext2 File System (non journaling)
ext3 File System - Red Hat Journaling File System
ddrescue - Data recovery tool
Equivalent Windows command: CHKDSK - Check Disk - check and repair disk problems