utmpdump (1)

utmpdump [options] [filename]

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.

-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

Display version information and exit.

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.

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.

Michael Krapp

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

The utmpdump command is part of the util-linux package and is available from

Linux Kernel Archive