UTMPDUMP(1) Linux System Administrator's Manual UTMPDUMP(1)NAME
utmpdump - dump UTMP and WTMP files in raw format
SYNOPSIS
utmpdump [-froh] filename
DESCRIPTION
utmpdump is a simple program to dump UTMP and WTMP files in raw format, so they can be examined.
OPTIONS -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.
BUGS
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.
AUTHOR
Michael Krapp
SEE ALSO last(1), w(1), who(1), utmp(5),
Februar 8, 2010 UTMPDUMP(1)
Check Out this Related Man Page
UTMPDUMP(1) User Commands UTMPDUMP(1)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 file-
name 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.
-V, --version
Display version information and exit.
-h, --help
Display help text 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
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.
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.
AUTHOR
Michael Krapp
SEE ALSO last(1), w(1), who(1), utmp(5)AVAILABILITY
The utmpdump command is part of the util-linux package and is available from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils
/util-linux/>.
util-linux July 2014 UTMPDUMP(1)
Here's a usefull perl script to trim the wtmp file,
in case it got too big, which happens sometimes, or got curropted (which also happens often).
You could learn from here how to parse the wtmp file...
but of course for just reading its content always simply use "last" like Neo said....
... (0 Replies)
Hi All,
if someone know where I can set dimension of utmp log files like
wtmp
failedlogin
sulog in an AIX system.
These are called security logs and they can reach a max amount in day or MB, where can I steady their size ?
thanks in advance. (2 Replies)
Hello, we recently upgraded from AIX 5.2.9 to 5.3.6 and in the process the wtmp file was cleared out. Before the upgrade the system had not been rebooted in a very long time, so i'm curious if the clearing of the file is related to the upgrade or the reboot? If it was related to the reboot is... (2 Replies)
Hi!
Letīs say I want copy dump-files to a location.
These dump-files vary between 80 and 280MB and will be produced in about 1min or less.
I have a cronjob which (not only) copies those.
So how can I find out whether a file is currently produced or not?
Because if my script works with these... (2 Replies)
Hali All,
I have a big problem. (REDHAT) I have a logrotate definition for wtmp:
/var/log/wtmp {
monthly
minsize 1M
create 0644 root utmp
rotate 9
}
There is a line for create the file with 0644 permission. If I run the definition manually it works as well, but when... (2 Replies)
New Unix user/scripter here. Been trying to solve a problem for two days now with no luck. Hoping someone here has an answer.
Essentially I have a list of wtmp files which I have decompressed and copied to a temporary directory. Using the following command I can turn them into a file than can... (4 Replies)
Hi,
Can anybody explain wtmp output fields?
A dir was created at 7:11pm and I wanted to find out who was logged in at that time but as you can see there is no ip address listed when I run utmpdump against the wtmp file.....
R,
D. (1 Reply)
Hi,
Does anyone have a script to truncate the wtmp file.
I want to move older entries in the wtmp to a new file and move it out of var/adm and shrink the size. (4 Replies)