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.\"     @(#)dumpfs.8	8.1 (Berkeley) 6/5/93
.\" $FreeBSD$
.\"
.Dd May 16, 2013
.Dt DUMPFS 8
.Os
.Sh NAME
.Nm dumpfs
.Nd dump UFS file system information
.Sh SYNOPSIS
.Nm
.Op Fl f
.Op Fl l
.Op Fl m
.Ar filesys | device
.Sh DESCRIPTION
The
.Nm
utility prints out the UFS super block and cylinder group information
for the file system or special device specified, unless the
.Fl f ,
.Fl l
or
.Fl m
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.
.Pp
If
.Fl 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.
.Pp
If
.Fl l
is specified, the pathname to the file system's container derived from
its unique identifier is printed.
.Pp
If
.Fl m
is specified, a
.Xr newfs 8
command is printed that can be used to generate a new file system
with equivalent settings.
Please note that
.Xr newfs 8
options
.Fl E ,
.Fl R ,
.Fl S ,
and
.Fl T
are not handled and
.Fl p
is not useful in this case so is omitted.
.Xr Newfs 8
options
.Fl n
and
.Fl r
are neither checked for nor output but should be.
The
.Fl r
flag is needed if the filesystem uses
.Xr gjournal 8 .
.Sh SEE ALSO
.Xr disktab 5 ,
.Xr fs 5 ,
.Xr disklabel 8 ,
.Xr fsck 8 ,
.Xr newfs 8 ,
.Xr tunefs 8
.Sh HISTORY
The
.Nm
utility appeared in
.Bx 4.2 .