1UTMPDUMP(1)                      User Commands                     UTMPDUMP(1)
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NAME

6       utmpdump - dump UTMP and WTMP files in raw format
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SYNOPSIS

9       utmpdump [options] [filename]
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DESCRIPTION

12       utmpdump is a simple program to dump UTMP and WTMP files in raw format,
13       so they can be examined.  utmpdump reads from stdin unless  a  filename
14       is passed.
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OPTIONS

17       -f, --follow
18              Output appended data as the file grows.
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20       -o, --output file
21              Write command output to file instead of standard output.
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23       -r, --reverse
24              Undump,  write  back  edited  login information into the utmp or
25              wtmp files.
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27       -V, --version
28              Display version information and exit.
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30       -h, --help
31              Display help text and exit.
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NOTES

34       utmpdump can be useful in cases of corrupted utmp or wtmp entries.   It
35       can  dump  out  utmp/wtmp to an ASCII file, which can then be edited to
36       remove bogus entries, and reintegrated using:
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38              utmpdump -r < ascii_file > wtmp
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40       But be warned, utmpdump was written for debugging purposes only.
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42   File formats
43       Only the binary version of the utmp(5) is standardised.  Textual  dumps
44       may become incompatible in future.
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46       The  version  2.28  was  the  last  one  that printed text output using
47       ctime(3) timestamp  format.   Newer  dumps  use  millisecond  precision
48       ISO-8601  timestamp  format  in UTC-0 timezone.  Conversion from former
49       timestamp format can be made to binary, although attempt to do  so  can
50       lead the timestamps to drift amount of timezone offset.
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BUGS

53       You  may  not  use the -r option, as the format for the utmp/wtmp files
54       strongly depends on the input format.  This tool was  not  written  for
55       normal use, but for debugging only.
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AUTHOR

58       Michael Krapp
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SEE ALSO

61       last(1), w(1), who(1), utmp(5)
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AVAILABILITY

64       The utmpdump command is part of the util-linux package and is available
65       from Linux Kernel Archive ⟨https://www.kernel.org/pub/linux/utils/util-
66       linux/⟩.
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70util-linux                         July 2014                       UTMPDUMP(1)
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