---
name: "dumpfs"
section: "8"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["freebsd", "openbsd"]
url: "https://new.carta.tech/dumpfs"
---

# dumpfs(8)

dump file system information

## NAME

**dumpfs** – dump file system information

## SYNOPSIS

**dumpfs** \[**-m**\] *filesys* \| *device*

## DESCRIPTION

**dumpfs** prints out the super block and cylinder group information for the file system or special device specified, unless **-m** is specified. The listing is very long and detailed.

**dumpfs** is useful mostly for finding out certain file system information such as the file system block size, minimum free space percentage, and the file system level that can be upgraded with the **-c** option of [fsck\_ffs(8)](/fsck_ffs/8.md). All of this information can be found within the first twenty lines of the output.

If **-m** is specified, a [newfs(8)](/newfs/8.md) command is output that can be used to generate a new file system with equivalent settings.

## SEE ALSO

[disktab(5)](/disktab/5.md), [fs(5)](/fs/5.md), [disklabel(8)](/disklabel/8.md), [fsck(8)](/fsck/8.md), [fsck\_ffs(8)](/fsck_ffs/8.md), [growfs(8)](/growfs/8.md), [newfs(8)](/newfs/8.md), [tunefs(8)](/tunefs/8.md)

## HISTORY

The **dumpfs** command appeared in 4.2BSD.