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/⟩.