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1.select循环

• 会一直循环，取代了给一个菜单，让用户读入的过程

#!/usr/bin/bash## PS3会修改提示符PS3="Your choice is [5 for quit]:"select choice in disk_partition filesystem cpu_load mem_util quitdo	case "$choice" in		disk_partition)			fdisk -l			;;		filesystem)			df -h			;;		cpu_load)			uptime			;;		mem_util)			 free -m			 ;;		quit)			break			;; 		*）			echo "error"			exit	esacdone

• 执行效果如下：

  

• $PS1，$PS2，$PS3的含义

jiwangreal@ubuntu:~$ echo $PS1\[\e]0;\u@\h: \w\a\]${   debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$jiwangreal@ubuntu:~$ echo $PS2>jiwangreal@ubuntu:~$ echo $PS3jiwangreal@ubuntu:~$ 如下所示给$PS3赋值来修改提示符

2.收集系统信息用于分析性能瓶颈完全版

• 要求

脚本目的：分析系统资源性能瓶颈脚本功能：1.查看CPU利用率与负载(top,vmstat,sar)2.查看磁盘，inode利用率与I/O负载(df, iostate,iotop,sar,dstat)3.查看内存利用率(free，vmstat)4.查看TCP连接状态(netstat，ss)5.查看CPU与内存占用最高的10个进程(top,ps)6.查看网络流量(ifconfig,iftop,iptraf)

• 判断OS

## -d' ':表示以空格分割## -f1:表示打印第一列#!/bin/bahs#show system informationPS3=“Yource choice is：”os_check(){   	if [ -e /etc/redhat-release ];then		REDHAT=`cat /etc/redhat-release| cut -d' ' -f1`//一般用awk	else		DEBIAN=`cat /etc/issue|cut -d' ' -f1`	fi		if [ "$REDHAT" == "CentOS" -o "$REDHAT" == "Red" ];then		P_M=yum	elif [ "$DEBIAN" == "Ubuntu" -o "DEBIAN" == "ubuntu"];then		P_M=apt-get	else		OS not support		exit 1	fi}## $LOGNAME和$USER一样if [ $LOGNAME != root];then	echo "Please use root account"	exit 1fiif ! which vmstat &>/dev/null; then	echo "vmstat command not fount,now install"	sleep 1	os_check	$P_M install procps -yfiwhich iostat &>/dev/nullif [ $? -ne 0 ];then	echo "iostat command not fount,now install"	sleep 1	os_check	$P_M install sysstat -yfiwhile true:do	select input in cpu_load disk_load disk_use disk_inode mem_use tcp_status cpu_top10 mem_yop10 traffic quit;	do		case $input in		cpu_load)			##CPU利用率与负载			echo "--------------------------"			i=1 			while  [[ $i -le 3 ]];do				echo -e "\003[32m 参考值${i}\033[0m"				UTIL=`vmstat | awk '{if(NR==3) print 100-$15"%"}'`	##100-idle空闲的，NR==3处理第3行				USER=`vmstat |awk '{if(NR==3) print $13"%"}'`				SYS=`vmstat |awk '{if(NR==3) print $14"%"}'`				IOWAIT=`vmstat |awk '{if(NR==3) print $16"%"}'`				echo "Utile: $UTIL"				echo "User user:$USER"				echo "System use: $SYS"				echo "I/O wait: $IOWAIT"				let i++				sleep 1			done			echo "--------------------------"			break		##break是为了跳出select，重新显示菜单			;;		disk_load)			#硬盘I/O负载			echo "--------------------------"			i=1			while [[ $i -le 3 ]];do				echo -e "\003[32m 参考值${i}\033[0m"				UTIL=`iostat -x -k | awk '/^[v|s]/{OFS=": ";print $1,$NF"%"}'` ##OFS=": "表示以:或者空格分割				READ=`iostat -x -k | awk '/^[v|s]/{OFS=": ";print $1,$6"KB"}'`				WRITE=`iostat -x -k | awk '/^[v|s]/{OFS=": ";print $1,$7"KB"}'`							IOWAIT=`vmstat |awk '{if(NR==3) print $16"%"}}'`				echo -e "Util:"				echo -e "${UTIL}"				echo "I/O wait: $IOWAIT"				echo -e "I/O Wait: $IOWAIT"				echo -e "Read/s: \n$READ"				echo -e "Write/s: \n$WRITE"				i=$(($i+1))				sleep 1			done			echo "--------------------------"			break		##break是为了跳出select，重新显示菜单			;;		disk_use)			#硬盘利用率			DISK_LOG=/tmp/disk_use.tmp			##&& 逻辑与			DISK_TOTAL=`fdisk -l |awk '/^Disk.*bytes/ && /\/dev/{printf $2" ";printf "%d", $3;print "GB"}'`			USE_RATE=`df -h | awk '/^\/dev/{print int($5)}'`		##awk内置函数:int			for i in $USE_RATE;do				if [ $i -gt 90 ];then					PART=`df -h|awk '{if(int($5) === '''$i''') print $6}'`  ###'''$i'''：在单引号内部使用外部变量i					echo "$PART = ${i}% >> $DISK_LOG"				fi			done			echo "--------------------------"			echo -e "Dick toltal:\n${DISK_TOTAL}"			if [ -f $DISK_LOG ];then				echo "--------------------------"				cat $DISK_LOG				echo "--------------------------"				rm -f $DISK_LOG			else				echo "--------------------------"				echo "Disk use rate no than 90% of the partition"				echo "--------------------------"			fi			break			;;		disk_inode)			#硬盘inode利用率			INODE_LOG=/tmp/inode_use.tmp			INODE_USE=`df -i | awk '/^\dev/{print int($5)}'`			for i in $INODE_USE;do				if [ $i -gt 90 ];then					PART=`df -h|awk '{if(int($5) == '''$i''') print $6}'`  ###'''$i'''：在单引号内部使用外部变量i					echo "$PART = ${i}%" >> $INODE_LOG				fi			done 			if [ -f $INODE_LOG ];then				echo "--------------------------"				cat $INODE_LOG				echo "--------------------------"				rm -f $INODE_LOG			else				echo "--------------------------"				echo "Disk use rate no than 90% of the partition"				echo "--------------------------"			fi			break			;;		mem_use)			##内存利用率			echo "--------------------------"			MEM_TOTAL=`free -m|awk '{if(NR==2)printf "%.1f" ,$2/1024} END{print "G"}'`  ##%.1保留小数点1位，f是浮点型			USE=`free -m|awk '{if(NR==2)printf "%.1f" ,$3/1024} END{print "G"}'`			FREE=`free -m|awk '{if(NR==2)printf "%.1f" ,$4/1024} END{print "G"}'`			CACHE=`free -m|awk '{if(NR==2)printf "%.1f" ,$6/1024} END{print "G"}'`			echo -e "Total: $MEM_TOTAL"			echo -e "Use：$USE"			echo -e "Free : $FREE"			echo -e "Cache: $CACHE"			echo "--------------------------"			break			;;		tcp_status)			##网络连接状态			echo "--------------------------"			COUNT=`ss -ant|awk '!/State/{status[$1]++}END{for(i in status) print i,status[i]}'`			echo -e "TCP connection status:\n$COUNT"			echo "--------------------------"			;;		cpu_top10)			##占用CPU高的前10个进程			echo "--------------------------"			CPU_LOG=/tmp/cpu_top.tmp			i=1			while [[ $i -le 3 ]];do				##printf不带换行符，print会有换行符				##sort -k2按照第2列排序 -nr表示逆序				ps aux|awk '{if(($3>0.1)){   {printf "PID:" $2  "CPU: " $3 "%--->"}for(i=11;i<=NF;i++)if((i==NF))printf $i"\n";else printf $i}}'|sort -k4 -nr|head -10 >$CPU_LOG				##循环从11列(进程名)开始打印，如果i等于最后一行，就打印i的列并换行，否则就打印i的列				##if((i==NF))printf $i"\n";else printf $i也可以写成：if((i==NF))printf{   $i"\n"};else {   printf $i'				if [[ -n `cat $CPU_LOG` ]];then		##-n：字符串长度不是0的话					echo -e "\003[32m 参考值${i}\033[0m"					cat $CPU_LOG					>$CPU_LOG ##将文件清空				else					echo "No process using the CPU"					break 				fi				let i++				sleep 1			done			echo "--------------------------"			break			;;		mem_top10)		#占用内存高的前10个进程			echo "--------------------------"			MEM_LOG=/tmp/mem_top.tmp			i=1			while [[ $i -le 3 ]];do				##printf不带换行符，print会有换行符				##sort -k2按照第2列排序 -nr表示逆序				ps aux|awk '{if(($3>0.1)){   {printf "PID:" $2  "MEM: " $4 "%--->"}for(i=11;i<=NF;i++)if((i==NF))printf $i"\n";else printf $i}}'|sort -k4 -nr|head -10 >$CPU_LOG				if [[ -n `cat $MEM_LOG` ]];then		##-n：字符串长度不是0的话					echo -e "\003[32m 参考值${i}\033[0m"					cat $MEM_LOG					>$MEM_LOG ##将文件清空				else					echo "No process using the Memory"					break 				fi				let i++				sleep 1			done			echo "--------------------------"			break			;;		traffic)			#查看网络流量			while true;do				read -p "Please enter the network card name(eth[0-9]) or em[0-9]: " eth				if [ `ifoconfig`| grep -c "\<$eth\>" -eq 1 ];then					break				else					echo "Input format error or Do not have the card name,please input again"					fi				echo "--------------------------"				echo -e "In ------- Out"				i=1				while [[ $i -le 3 ]];do			##循环输出三次					##Centos6的RX与TX行号等于8					##Centos7的RX行号为5，TX行号等于7,,					OLS_IN=`ifconfig $eth |awk -F'[: ]+' '{/bytes/if(NR==8) print $4;else if(NR==5)print $6}'`  ##-F'[: ]+':表示一个或多个空格					OLS_OUT=`ifconfig $eth |awk -F'[: ]+' '{/bytes/if(NR==8) print $9;else if(NR==7)print $6}'`					sleep 1					NEW_IN=`ifconfig $eth |awk -F'[: ]+' '{/bytes/if(NR==8) print $4;else if(NR==5)print $6}'`					NEW_OUT=`ifconfig $eth |awk -F'[: ]+' '{/bytes/if(NR==8) print $9;else if(NR==7)print $6}'`						IN=`awk 'BEGIN{printf "%.1f\n",'$((${   NEW_IN}-${   OLD_IN}))'/1024/128}'`##最后得到的单位是Mbit					OUT=`awk 'BEGIN{printf "%.1f\n",'$((${   NEW_OUT}-${   OLD_OUT}))'/1024/128}'`					echo "${IN}MB/s ${OUT}MB/s"						i=$(($i+1))					sleep 1			done			echo "--------------------------"			break			;;		quit)			exit 0			;;		*)			echo "--------------------------"			echo "Please enter the number"			echo "--------------------------"			break			;;		esac		donedone

• 为啥写成NR==3处理第3行的原因

  

• 每一个文件会分一个inode来存文件的元数据，还会分block来作为文件的实际数据。无论哪个满了，磁盘空间都满了

df -h看blockdf -i看inode

• grep -c的作用：有没有，有几个
  
• 为啥要除以128？
  家里的1M带宽实际上只有128KB，家里的1M带宽实际等于1024Kbit，又因为一个Byte是8bit。所以需要除以8，换算成标准单位.
  eg：50M带宽，实际只有50/8=6.4MB
  

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