유닉스 unix awk gawk 와 모든 유틸리티를 사용하여 하는건데요

$ cat last.sh
#!/bin/bash
 
LAST_OPTS="-R"
[ -n "$1" -a -f "$1" ] && LAST_OPTS+=" -f $1"
 
declare -a users ltimes lcounts
 
sec_to_dhms()
{
	let local d=${1}/86400
	let local h=(${1}%86400)/3600
	let local m=(${1}%3600)/60
	let local s=${1}%60
 
	printf "%d days and %02d:%02d:%02d" $d $h $m $s
}
 
print_users_logtime()
{
	local i=0
	while [ $i -lt ${#users[@]} ]
	do
		echo "${users[$i]}	: ${lcounts[$i]-0} logins for $(sec_to_dhms ${ltimes[$i]-0}) (${ltimes[$i]-0} seconds)"
		let i++
	done
}
 
put_user_ltime()
{
	local i=0
	while [ $i -lt ${#users[@]} ]
	do
		[ "${users[$i]}" = "$1" ] && break
		let i++
	done
	[ $i -eq ${#users[@]} ] && users+=("$1")
 
	[[ $2 == *+* ]] && day=$(expr ${2/+*} \* 86400) || day=0
	hm=${2/*+}
	secs=$(expr $day + ${hm/:*} \* 3600 + ${hm/*:})
 
	let ltimes[$i]=${ltimes[$i]-0}+$secs
	let lcounts[$i]++
}
 
last $LAST_OPTS | sort | grep -v ^reboot > .last.tmp
while read -r line
do
	user=$(echo $line | awk '{print $1}')
	ltime=$(echo $line | sed -n 's/.*(\(.*\)).*/\1/p')
	[ -z "$ltime" ] && continue
	put_user_ltime $user $ltime
done < .last.tmp
/bin/rm -f .last.tmp
 
print_users_logtime
 
exit 0;
 
$ ./last.sh
******  : 12 logins for 1 days and 08:04:01 (115441 seconds)
****    : 6 logins for 0 days and 12:01:24 (43284 seconds)
****    : 12 logins for 0 days and 00:00:07 (7 seconds)
******* : 18 logins for 8 days and 21:11:47 (767507 seconds)
$ ./last.sh /var/log/wtmp.1
******  : 43 logins for 4 days and 17:16:00 (407760 seconds)
******* : 1 logins for 0 days and 01:00:36 (3636 seconds)
****    : 61 logins for 7 days and 13:18:39 (652719 seconds)
****    : 22 logins for 17 days and 22:06:26 (1548386 seconds)
******* : 28 logins for 19 days and 14:11:43 (1692703 seconds)