#!/bin/bash

while true

do

load=`w|head -1|awk -F'load average: ' '{print $2}'|cut -d. -f1`

if [ $load -gt 10 ]

then

echo $load

fi

sleep 30

done

#!/bin/bash

while true

do

    read -p "Please input a number:" n

    if [ -z "$n" ]

    then

        echo "you need input sth"

        continue

     fi

     n1=`echo $n|sed 's/[0-9]//g'`

     if [ -n "$n1" ]

     then

        echo "you just only input numbers"

        continue

     fi

      break

done

echo $n