AIX stores the last time a user changed their password as a "epoch" time stamp, or in other words as the number of seconds since 1970.
For example, if you want to see when the last time root changed their password you can type:
# lsuser -a lastupdate root
root lastupdate=1391663150
This shows that root changed their password at 1,391,663,150 seconds after 1970. In other words, this really isn't very helpful unless you take this epoch number and convert it to a real date.
Here is a one liner function that will give you a "lastpwchg" command that will show a normal date/time for a users last password change. Just type "lastpwchg" followed by the username you would like to check:
function lastpwchg { [ "`whoami`" = "root" ] || { echo "Must be root"; return; }; printf "$1: "; lastupdate=`lsuser -a lastupdate $1 2>/dev/null | awk -F= "{print \\$2}"`; [ -n "$lastupdate" ] && perl -e "print \"Last password change: \" . scalar (localtime($lastupdate)) . \"\n\" " || echo "User does not exist or has no lastupdate attribute"; }
You can add this one liner to your .profile so it is always available when you login.
The results look like this when you run it to check a user:
# lastpwchg root
root: Last password change: Wed Feb 5 23:05:50 2014
#
# lastpwchg padmin
padmin: Last password change: Wed Nov 14 21:29:58 2013
If you found this useful, you might also want to check out this post: Don't let your AIX passwords expire