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.

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

       -V, --version
           Print version 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.

AUTHORS

       Michael Krapp

SEE ALSO

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

REPORTING BUGS

       For bug reports, use the issue tracker at https://github.com/util-linux/util-linux/issues.

AVAILABILITY

       The utmpdump command is part of the util-linux package which can be downloaded from Linux
       Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.