xref: /freebsd/sbin/dumpfs/dumpfs.8 (revision ca987d4641cdcd7f27e153db17c5bf064934faf5)
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28.\"     @(#)dumpfs.8	8.1 (Berkeley) 6/5/93
29.\" $FreeBSD$
30.\"
31.Dd May 16, 2013
32.Dt DUMPFS 8
33.Os
34.Sh NAME
35.Nm dumpfs
36.Nd dump UFS file system information
37.Sh SYNOPSIS
38.Nm
39.Op Fl f
40.Op Fl l
41.Op Fl m
42.Ar filesys | device
43.Sh DESCRIPTION
44The
45.Nm
46utility prints out the UFS super block and cylinder group information
47for the file system or special device specified, unless the
48.Fl f ,
49.Fl l
50or
51.Fl m
52flag is specified.
53The listing is very long and detailed.
54This
55command is useful mostly for finding out certain file system
56information such as the file system block size and minimum
57free space percentage.
58.Pp
59If
60.Fl f
61is specified, a sorted list of all free fragments and free fragment ranges,
62as represented in cylinder group block free lists, is printed.
63If the flag is specified twice, contiguous free fragments are not collapsed
64into ranges and instead printed in a simple list.
65Fragment numbers may be converted to raw byte offsets by multiplying by the
66fragment size, which may be useful when recovering deleted data.
67.Pp
68If
69.Fl l
70is specified, the pathname to the file system's container derived from
71its unique identifier is printed.
72.Pp
73If
74.Fl m
75is specified, a
76.Xr newfs 8
77command is printed that can be used to generate a new file system
78with equivalent settings.
79Please note that
80.Xr newfs 8
81options
82.Fl E ,
83.Fl R ,
84.Fl S ,
85and
86.Fl T
87are not handled and
88.Fl p
89is not useful in this case so is omitted.
90.Xr Newfs 8
91options
92.Fl n
93and
94.Fl r
95are neither checked for nor output but should be.
96The
97.Fl r
98flag is needed if the filesystem uses
99.Xr gjournal 8 .
100.Sh SEE ALSO
101.Xr fs 5 ,
102.Xr fsck 8 ,
103.Xr gpart 8 ,
104.Xr newfs 8 ,
105.Xr tunefs 8
106.Sh HISTORY
107The
108.Nm
109utility appeared in
110.Bx 4.2 .
111