topic Re: clear the wtmp file in Operating System - HP-UX

clear the wtmp file

Ratzie — Mon, 08 Dec 2003 14:15:30 GMT

How would I go about clearing the wtmp file?

When I do a last|more it is quite huge, and this machine is not in production yet, so I would like to clear it out, and at least keep the first time the system was brought up.

Is there a file to change?

Re: clear the wtmp file

Karthik S S — Mon, 08 Dec 2003 14:16:22 GMT

>wtmp

is what you need ...

-Karthik S S

Re: clear the wtmp file

Geoff Wild — Mon, 08 Dec 2003 14:19:51 GMT

I think you can do this:

cat /dev/null > /var/adm/wtmp

Rgds...Geoff

Re: clear the wtmp file

Michael Schulte zur Sur — Mon, 08 Dec 2003 14:24:22 GMT

Hi,

you also can do it with
cp /dev/null /var/adm/wtmp

greetings,

Michael

Re: clear the wtmp file

RAC_1 — Mon, 08 Dec 2003 14:28:15 GMT

> /var/adm/wtmp
cat /dev/null > /var/adm/wtmp

But do you have any issues with that? Is who reporting wrong details etc?

Then I would advise you to check wtmp patches.

Also have a look at fwtmp command. With command you can check wtmp file and fix it.

Re: clear the wtmp file

Helen French — Mon, 08 Dec 2003 14:35:57 GMT

You can make these type of routine maintenance tasks through SAM. Instead of nullyfying the entire wtmp file, you can easily "trim" your log files including wtmp file. This is a good way of maintining system log files.

# sam -> Routine Tasks ->

Re: clear the wtmp file

Jeff Ohlhausen — Mon, 08 Dec 2003 15:36:57 GMT

The best and easiset way is to use SAM:
- administration
- log files
Trim it to the selected amount.

Re: clear the wtmp file

H.Merijn Brand (procura — Fri, 28 May 2004 03:30:10 GMT

SAM does not work on AIX :}

--8<--- Script to reduce wtmp file to sensible size
#!/opt/perl/bin/perl

use strict;
use warnings;
use User::Utmp;

my ($n, $s, $treshold, @wtmp, %type) = (0, 0, time - 7 * 24 * 60 * 60); # One week should do
User::Utmp::utmpname (shift || "wtmp");
User::Utmp::setutent ();
while (my @entry = User::Utmp::getut1 ()) {
++$n % 100 or printf STDERR " %6d %6d\r", $n, $s;
if ( $entry[0]->{ut_type} == LOGIN_PROCESS &&
$entry[0]->{ut_time} > 0 && $entry[0]->{ut_time} < $treshold) {
$s++;
next;
}
push @wtmp, @entry;
}
User::Utmp::endutent ();

print STDERR "wtmp has $n entries, I skipped $s\n";
#print STDERR "[ ", (join ", ", map { "$_ => $type{$_}" } sort { $a <=> $b } keys %type), " ]\n";

User::Utmp::utmpname ("/tmp/wtmp");
User::Utmp::putut ($_) for @wtmp;
User::Utmp::endutent ();
-->8---

i2:/var/adm 126 # clrwtmp.pl
wtmp has 359424 entries, I skipped 358595
i2:/var/adm 127 # ll wtmp /tmp/wtmp
263 -rw-r--r-- 1 root system 1920 May 28 10:24 /tmp/wtmp
2074 -rw-r--r-- 1 root system 23003136 Jan 20 08:51 wtmp
i2:/var/adm 128 # mv /tmp/wtmp wtmp

All relevant info retained this way (boot time and such)

Enjoy, Have FUN! H.Merijn