命令

a=`date +%s`
b=`expr $a - 2592000`
c=`date -d @$b "+%Y%m%d%H%M%S"`
l_total=`lastb |grep -v btmp |grep -v ^$ |wc -l`
l_befor=`lastb -t $c |grep -v btmp |grep -v ^$ |wc -l`
l_end=`expr $l_total - $l_befor`
lastb=`lastb |sed -n 1,${l_end}p |wc -l`
if [ $lastb -gt ${login_failed_times} ];then
    echo "login_failed_times=${lastb}@@1"
else
    echo "login_failed_times=${lastb}@@0"
fi

结果

login_failed_times=337718@@0