xref: /freebsd/sbin/dumpfs/dumpfs.8 (revision bdd1243df58e60e85101c09001d9812a789b6bc4)
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28.\"     @(#)dumpfs.8	8.1 (Berkeley) 6/5/93
29.\" $FreeBSD$
30.\"
31.Dd July 2, 2021
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.Op Fl s
43.Ar filesys | device
44.Sh DESCRIPTION
45The
46.Nm
47utility prints out the UFS super block and cylinder group information
48for the file system or special device specified, unless the
49.Fl f ,
50.Fl l ,
51.Fl m ,
52or
53.Fl s
54flag is specified.
55The listing is very long and detailed.
56This
57command is useful mostly for finding out certain file system
58information such as the file system block size and minimum
59free space percentage.
60.Pp
61If
62.Fl f
63is specified, a sorted list of all free fragments and free fragment ranges,
64as represented in cylinder group block free lists, is printed.
65If the flag is specified twice, contiguous free fragments are not collapsed
66into ranges and instead printed in a simple list.
67Fragment numbers may be converted to raw byte offsets by multiplying by the
68fragment size, which may be useful when recovering deleted data.
69.Pp
70If
71.Fl l
72is specified, the pathname to the file system's container derived from
73its unique identifier is printed.
74.Pp
75If
76.Fl m
77is specified, a
78.Xr newfs 8
79command is printed that can be used to generate a new file system
80with equivalent settings.
81Please note that
82.Xr newfs 8
83options
84.Fl E ,
85.Fl R ,
86.Fl S ,
87and
88.Fl T
89are not handled and
90.Fl p
91is not useful in this case so is omitted.
92The
93.Xr newfs 8
94options
95.Fl n
96and
97.Fl r
98are neither checked for nor output but should be.
99The
100.Fl r
101flag is needed if the filesystem uses
102.Xr gjournal 8 .
103.Pp
104If
105.Fl s
106is specified, only the super block information is printed.
107.Sh SEE ALSO
108.Xr fs 5 ,
109.Xr fsck 8 ,
110.Xr gpart 8 ,
111.Xr newfs 8 ,
112.Xr tunefs 8
113.Sh HISTORY
114The
115.Nm
116utility appeared in
117.Bx 4.2 .
118