---
title: fsck (file system check) — File system integrity check and repair
date: 2026-10-20
time: 12:00
model: admin
category: programs
author_type: human
summary: A checking tool that verifies file system metadata and repairs errors interactively.
tags: program, File and disk management, fsck
---

A checking tool that verifies file system metadata and repairs errors interactively.

## Basic Information

| Command Name | fsck (file system check) |
| --- | --- |
| One-line Introduction | A checking tool that verifies file system metadata and repairs errors interactively. |
| Provided by | e2fsprogs / util-linux (preinstalled on most distributions) |
| Official Documentation | https://man7.org/linux/man-pages/man8/fsck.8.html |
| Supported Operating Systems | Linux, WSL |
| Installation Status | Installed by default (no separate installation needed) |
| Category | Linux file and disk management (tags: filesystem, check, repair, e2fsck) |

## What is this command?

fsck checks the superblock, inodes and block bitmaps of a file system to find damaged metadata. Depending on the file system type it delegates to a tool such as e2fsck or xfs_repair.

It must be run on an unmounted file system; during boot systemd performs the check automatically. The run may continue with interactive prompts asking whether to repair each problem.

## What problems does it solve?

- A file system may be damaged after an unclean shutdown
- Mounting fails with metadata corruption messages
- You want to verify integrity before replacing a disk
- The boot-time check keeps repeating
## Key features

### Read-only check

The -n option reports problems without changing anything.

- **When to use**: You want a diagnosis before changing anything
- **What you get**: A summary of found errors and an exit code
- **Limitations**: The file system stays untouched even if errors remain.
### Automatic repair

The -y option answers yes to every question and repairs in bulk.

- **When to use**: You have a backup and need a fast repair
- **What you get**: A repaired file system
- **Limitations**: An incorrect repair can damage data further.
### File system specific tools

ext4 uses e2fsck, XFS uses xfs_repair and Btrfs uses btrfs check.

- **When to use**: You need a check tailored to one file system
- **What you get**: Results from the appropriate checker
- **Limitations**: Options and repair policies differ between tools.
## Installation and usage

### Check whether it is installed

```
fsck --version
```

sudo apt install e2fsprogs   # Debian/Ubuntu
sudo dnf install e2fsprogs   # Fedora

## Real-world examples

### Read-only check

Unmount the file system, then check without changes.

```
sudo umount /dev/sdb1
sudo fsck -n /dev/sdb1
```

### Repair automatically

Repair in bulk when a backup exists.

```
sudo fsck -y /dev/sdb1
```

### ext4 specific check

Use e2fsck and also scan for bad blocks.

```
sudo e2fsck -f -c /dev/sdb1
```

---
Source (HTML): https://games.aidebatehub.com/programs/linux/filesystem/fsck.html
This file is an auto-generated Markdown twin of the DevHub document.