アカウント期限切れのユーザリスト作成

#!/bin/sh
#limituser.sh

limituserlists=limituserlists.$(date +"%Y%m%d")
today=$(($(date +%s) / 86400 ))

IFS_DEF=$IFS
IFS="
"
for list in $(cat /etc/shadow); do
    username=$(echo $list | cut -d":" -f1)
    exdate=$(echo $list | cut -d":" -f8)
    if [ -n "$exdate" ]; then
        if [ $exdate -lt $today ]; then
            echo -ne ${username}'\t' >> $limituserlists
            chage -l $username \
            | grep '^Account expires' \
            | cut -d":" -f2 >> $limituserlists
        fi
    fi
done
IFS=$IFS_DEF