xref: /freebsd/sbin/dumpfs/dumpfs.8 (revision 4f8f43b06ed07e96a250855488cc531799d5b78f)
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28.\"     @(#)dumpfs.8	8.1 (Berkeley) 6/5/93
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30.Dd July 2, 2021
31.Dt DUMPFS 8
32.Os
33.Sh NAME
34.Nm dumpfs
35.Nd dump UFS file system information
36.Sh SYNOPSIS
37.Nm
38.Op Fl f
39.Op Fl l
40.Op Fl m
41.Op Fl s
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 ,
50.Fl m ,
51or
52.Fl s
53flag is specified.
54The listing is very long and detailed.
55This
56command is useful mostly for finding out certain file system
57information such as the file system block size and minimum
58free space percentage.
59.Pp
60If
61.Fl f
62is specified, a sorted list of all free fragments and free fragment ranges,
63as represented in cylinder group block free lists, is printed.
64If the flag is specified twice, contiguous free fragments are not collapsed
65into ranges and instead printed in a simple list.
66Fragment numbers may be converted to raw byte offsets by multiplying by the
67fragment size, which may be useful when recovering deleted data.
68.Pp
69If
70.Fl l
71is specified, the pathname to the file system's container derived from
72its unique identifier is printed.
73.Pp
74If
75.Fl m
76is specified, a
77.Xr newfs 8
78command is printed that can be used to generate a new file system
79with equivalent settings.
80Please note that
81.Xr newfs 8
82options
83.Fl E ,
84.Fl R ,
85.Fl S ,
86and
87.Fl T
88are not handled and
89.Fl p
90is not useful in this case so is omitted.
91The
92.Xr newfs 8
93options
94.Fl n
95and
96.Fl r
97are neither checked for nor output but should be.
98The
99.Fl r
100flag is needed if the filesystem uses
101.Xr gjournal 8 .
102.Pp
103If
104.Fl s
105is specified, only the super block information is printed.
106.Sh SEE ALSO
107.Xr fs 5 ,
108.Xr fsck 8 ,
109.Xr gpart 8 ,
110.Xr newfs 8 ,
111.Xr tunefs 8
112.Sh HISTORY
113The
114.Nm
115utility appeared in
116.Bx 4.2 .
117