Section (1) utmpdump
utmpdump — dump UTMP and WTMP files in raw format
a simple program to dump UTMP and WTMP files in raw format,
so they can be examined. utmpdump reads from stdin
Output appended data as the file grows.
Write command output to file instead of standard output.
Undump, write back edited login information into the utmp or wtmp files.
Display version information and exit.
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.
The only 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.
You may not use the
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
Copyright (C) 2010 Michael Krapp
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA