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DUMPFS(8) FreeBSD System Manager's Manual DUMPFS(8)
NAME
dumpfs - dump UFS file system information
SYNOPSIS
dumpfs [-f] [-l] [-m] [-s] filesys | device
DESCRIPTION
The dumpfs utility prints out the UFS super block and cylinder group
information for the file system or special device specified, unless the
-f, -l, -m, or -s flag is specified. The listing is very long and
detailed. This command is useful mostly for finding out certain file
system information such as the file system block size and minimum free
space percentage.
If -f is specified, a sorted list of all free fragments and free fragment
ranges, as represented in cylinder group block free lists, is printed.
If the flag is specified twice, contiguous free fragments are not
collapsed into ranges and instead printed in a simple list. Fragment
numbers may be converted to raw byte offsets by multiplying by the
fragment size, which may be useful when recovering deleted data.
If -l is specified, the pathname to the file system's container derived
from its unique identifier is printed.
If -m is specified, a newfs(8) command is printed that can be used to
generate a new file system with equivalent settings. Please note that
newfs(8) options -E, -R, -S, and -T are not handled and -p is not useful
in this case so is omitted. The newfs(8) options -n and -r are neither
checked for nor output but should be. The -r flag is needed if the
filesystem uses gjournal(8).
If -s is specified, only the super block information is printed.
SEE ALSO
fs(5), fsck(8), gpart(8), newfs(8), tunefs(8)
HISTORY
The dumpfs utility appeared in 4.2BSD.
FreeBSD 14.2-RELEASE July 2, 2021 FreeBSD 14.2-RELEASE