Provided by: util-linux_2.27.1-6ubuntu3_amd64
utmpdump - dump UTMP and WTMP files in raw format
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. -V, --version Display version information and exit. -h, --help Display help text 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.
The utmpdump command is part of the util-linux package and is available from Linux Kernel Archive ⟨ftp://ftp.kernel.org/pub/linux/utils/util-linux/⟩.