utmpdump

UTMPDUMP(1)                      User Commands                     UTMPDUMP(1)

NAME
       utmpdump - dump UTMP and WTMP files in raw format

SYNOPSIS
       utmpdump [options] [filename]

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

OPTIONS
       -f, --follow
              Output appended data as the file grows.

       -o, --output file
              Write command output to file instead of standard output.

       -r, --reverse
              Undump,  write  back  edited  login information into the utmp or
              wtmp files.

       -V, --version
              Display version information and exit.

       -h, --help
              Display help text and exit.

NOTES
       utmpdump can be useful in cases of corrupted utmp or wtmp entries.   It
       can  dump  out  utmp/wtmp to an ASCII file, which can then be edited to
       remove bogus entries, and reintegrated using:

              utmpdump -r < ascii_file > wtmp

       But be warned, utmpdump was written for debugging purposes only.

   File formats
       Only the binary version of the utmp(5) is standardised.  Textual  dumps
       may become incompatible in future.

       The  version  2.28  was  the  last  one  that printed text output using
       ctime(3) timestamp  format.   Newer  dumps  use  millisecond  precision
       ISO-8601  timestamp  format  in UTC-0 timezone.  Conversion from former
       timestamp format can be made to binary, although attempt to do  so  can
       lead the timestamps to drift amount of timezone offset.

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

AUTHOR
       Michael Krapp

SEE ALSO
       last(1), w(1), who(1), utmp(5)

AVAILABILITY
       The utmpdump command is part of the util-linux package and is available
       from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-
       linux/>.

util-linux                         July 2014                       UTMPDUMP(1)