UTMPDUMP(1) Linux System Administrator's Manual UTMPDUMP(1)

utmpdump - dump UTMP and WTMP files in raw format

utmpdump [-froh] filename

utmpdump is a simple program to dump UTMP and WTMP files in raw format, so they can be examined.

-f
output appended data as the file grows.
-r
reverse. Write back edited login information into utmp or wtmp files.
-o
use old libc5 format.
-h
usage information.

utmpdump can be useful in cases of corrupted utmp or wtmp entries. It can dump out utmp/wtmp to an ASCII file, then that file can be edited to remove bogus entries and reintegrated, using


utmpdump -r < ascii file > wtmp

but be warned as utmpdump was written for debugging purpose only.

You may not use the option -r 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.

Michael Krapp

last(1), w(1), who(1), utmp(5),
Februar 8, 2010