Path: utzoo!mnetor!uunet!husc6!cmcl2!brl-adm!umd5!purdue!i.cc.purdue.edu!j.cc.purdue.edu!h.cc.purdue.edu!s.cc.purdue.edu!rsk
From: rsk@s.cc.purdue.edu (Rock Wombat)
Newsgroups: news.admin
Subject: Re: Arbitron "Users" count is very wrong under BSD
Message-ID: <1978@s.cc.purdue.edu>
Date: 19 Jan 88 16:07:08 GMT
References: <15538@onfcanim.UUCP>
Reply-To: rsk@s.cc.purdue.edu.UUCP (Rock Wombat)
Organization: Purdue Computing Center Unix Systems Staff
Lines: 15

In article <15538@onfcanim.UUCP> dave@onfcanim.UUCP (Dave Martindale) writes:
>On BSD unix, arbitron generally uses the pipeline
>  nusers=`last | sort -u +0 -1 | wc -l`
>to count the number of users who have logged in this month, in order to
>ignore dormant users in the passwd file.

This can also result in a count that is too low.  On our systems, we zero
the utmp and wtmp files every 24 hours, so this pipeline would only reveal
those users who have logged in since the last zap.  I'm not sure that there's
a good solution to this problem; is there a general way to answer the question
"How many active users does this machine have?" that avoids this difficulty?

-- 
Rich Kulawiec, rsk@s.cc.purdue.edu, s.cc.purdue.edu!rsk
PUCC Unix Staff