Shell脚本监控CPU、内存和硬盘利用率

在linux 下如何使用shell脚本来监控系统的cpu，内存和硬盘的使用率呢。请参考下面的脚本。
1、监控CPU利用率（通过vmstat工具）

#!/bin/bash
if [ `uname` != "Linux" ];then
       echo "check os not linux."
       exit 1
fi
which vmstat &>/dev/null
if [ $? -ne 0 ];then
       echo "vmstat command no found, please install procps package."
        exit 1
fi
cpu_us=`vmstat | awk '{print $13}' | sed -n '$p'`
cpu_sy=`vmstat | awk '{print $14}' | sed -n '$p'`
cpu_id=`vmstat | awk '{print $15}' | sed -n '$p'`
cpu_wa=`vmstat | awk '{print $16}' | sed -n '$p'`   #等待I/0完成
cpu_sum=$(($cpu_us+$cpu_sy))
cpu_info()
{echo "CPU_Sum : $cpu_sum% ( CPU_Use:${cpu_us}% , CPU_System:${cpu_sy}% )"
 echo "CPU_Idle : ${cpu_id}%"<br />echo "CPU_Wait : ${cpu_wa}"}
#cpu_info;<br />if [ $cpu_sum -ge 90 ];then
       echo "CPU utilization $cpu_sum." | mail -s "CPU Monitor" baojingtongzhi@163.com
fi
 

2、监控内存利用率

#!/bin/bash
which bc &>/dev/null
if [ $? -ne 0 ];then
       echo "bc command no found, Please install bc package."
       exit 1
fi
Date=`date +%F" "%H:%M`
IP=`ifconfig eth0 | awk '/inet addr/ {print $2}' | cut -d: -f2`
Total=`free -m | grep Mem | awk '{print $2}'`
Use=`free -m | awk '/buffers\// {print $NF}'`
Free=$(($Total-$Use))
Total_conv=`echo "scale=2;$Total/1024" | bc | awk '{print $1"G"}'`  #通过bc计算，保留小数点后两位（scale）
if [ $Free -lt 200 ];then
        Content=`echo -e "Date : $Date \nHost : $IP \nTotal : ${Total_conv} \nUse : ${Use}M \nFree : ${Free}M"`
        echo "$Content" | mail -s "Memory Monitor" baojingtongzhi@163.com
fi
 

3、监控磁盘利用率

#!/bin/bash
Date=`date +%F" "%H:%M`
IP=`ifconfig eth0 | awk '/inet addr/ {print $2}' | cut -d: -f2`
Total=`fdisk -l | grep "Disk /dev/sd[a-z]" |awk '{print $2$3"GB"}' |sed 's/:/=/'`
Disk_Use=`df -h |awk '{print $1"="$5}' | sed '1d' | sed 's/%//g'`
for i in $Disk_Use
do
       A=`echo $i |awk -F'=' '{print $2}'`
       if [ $A -gt 8 ];then
               echo -e "Date : $Date \nHost : $IP \nTotal : $Total \nProblem : Part Use ${i}%" | mail -s "Disk Monitor" aaa@163.com
      fi
done