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Unix 책에 있는건데요.. 주석은 안넣었습니다...
틀린곳이 3부분이 있다고 합니다...그리고 각줄에대한 설명을좀
부탁드립니다....
#!/bin/sh
pause=20
loopCount=10000
error=0
for arg in $*
do
	case $arg in
		-t*)
			pause=`expr substr $arg 3 10`
			;;
		-n*)
			loopCount=`expr substr $arg 3 10`
			;;
		*)
			user=$arg
			;;
	esac
done
if [ ! "$user" ]
then
	error
fi
if [ $error -eq 1 ]
then
	cat << ENDOFERROR
usage: track [-n#] [-t#] userId
ENDOFERROR
	exit 1
fi
trap 'track.cleanip $$; exit $exitCode' 0
trap 'exitCode=1; exit' 2 3
echo -n > .track.old.$$
count=0
while [ $count -lt $loopCount ]
do
	who | grep $user | sort > .track.new.$$
	diff .track.new.$$ .track.old.$$ | sed -f track.sed > .track.report.$$
	if [ -s .track.report.$$ ]
	then
		echo track report for ${user}:
		cat .track.report.$$
	fi
	mv .track.new.$$.track.old.$$
	sleep $pause
	count=`expr $count + 1`
done
exitCode=0
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