1.150 How can I reduce the size of /var/adm/wtmp ?

The file /var/adm/wtmp grows with each login, but is never reduced.
The contents of wtmp is used (only?) by the command "last",
which shows, in reverse order, all the logins and reboots that
happened since the start of the wtmp file.

The file should not be deleted, but the contents can be discarded using
the following command:
# > /var/adm/wtmp

Alternatively the freeware utility "tidysys" can remove all the entries
from wtmp that are older than (say) 15 days. Tidysys was written by
Terry Murray <terry@weavel.demon.co.uk> for AIX 3.2 and is available
from ftp://ftp.frontiernet.net/pub/aix/.

Tidysys was ported to AIX 4.1 by C. Deignan and is available from
<http://www-frec.bull.com/>.