🚀 go-pugleaf

In article <9205201503.AA01446@moore.com> paul@moore.com (Paul Maclauchlan) writes:
> Is there a utility that I can use to trim the contents of the wtmp
> file from the "top"?

Ideally you'd want to chop it off at a given date, but this would
require a bit of programming.

However, if you want to simply chop off some number of records from
the file, dd can do the job (example specific to SysVr3.1):

	wtmprecsize=36		# this is the number 'sizeof(struct utmp)'
	nchop=1000		# how many records to chop off
	dd if=wtmp of=wtmp.tmp bs=$wtmprecsiz skip=$nchop
	cp wtmp.tmp wtmp	# must not use mv in case file is open

I presume this is simply to satisfy users of last(1)....  If not, then
why not just roll over the wtmp file every day/week/month?

Instead of relying on last(1), I use a custom version of finger(1) and
something I call lastlog(1m) [since my login(1m) doesn't update
/usr/adm/lastlog].  Then the following shell function tells me when
everyone last logged in:

	function lastlog
	{
		YearGrep="grep `date +%Y`"
		if [ $# -eq 1 -a "$1" = "-a" ] ; then
			YearGrep="grep -v 1969"
		elif [ $# -ne 0 ] ; then
			echo 'Usage: lastlog [-a]' >&2
		fi
		/usr/lib/acct/fwtmp < /usr/adm/lastlog.ut | $YearGrep |
			oawk '{printf("%-8s %-12s %s\n", $1, $3, substr($0, 56))}'
	}

Both finger(1) and lastlog(1m) can be found in robohack!~/finger.T.Z.
-- 
						Greg A. Woods

woods@robohack.UUCP woods@Elegant.COM  VE3TCP	UniForum Canada & ECI
+1 416 443-1734 [home] +1 416 595-5425 [work]	Toronto, Ontario; CANADA