有哪些常用的shell脚本

先了解下编写Shell过程中注意事项：

开头加解释器：#!/bin/bash语法缩进，使用四个空格；多加注释说明。命名建议规则：变量名大写、局部变量小写，函数名小写，名字体现出实际作用。默认变量是全局的，在函数中变量local指定为局部变量，避免污染其他作用域。有两个命令能帮助我调试脚本：set -e 遇到执行非0时退出脚本，set-x 打印执行过程。写脚本一定先测试再到生产上。

1、获取随机字符串或数字

获取随机8位字符串：方法1：# echo $RANDOM |md5sum |cut -c 1-8471b94f2方法2：# openssl rand -base64 4vg3BEg==方法3：# cat /proc/sys/kernel/random/uuid |cut -c 1-8ed9e032c获取随机8位数字：方法1：# echo $RANDOM |cksum |cut -c 1-823648321方法2：# openssl rand -base64 4 |cksum |cut -c 1-838571131方法3：# date +%N |cut -c 1-869024815cksum：打印CRC效验和统计字节

2、定义一个颜色输出字符串函数

方法1：function echo_color() {   if [ $1 == "green" ]; then       echo -e "\033[32;40m$2\033[0m"   elif [ $1 == "red" ]; then       echo -e "\033[31;40m$2\033[0m"   fi}方法2：function echo_color() {   case $1 in       green)           echo -e "[32;40m$2[0m"           ;;       red)           echo -e "[31;40m$2[0m"           ;;       *)           echo "Example: echo_color red string"   esac}使用方法：echo_color green "test"function关键字定义一个函数，可加或不加。

3、批量创建用户

#!/bin/bashDATE=$(date +%F_%T)USER_FILE=user.txtecho_color(){   if [ $1 == "green" ]; then       echo -e "[32;40m$2[0m"   elif [ $1 == "red" ]; then       echo -e "[31;40m$2[0m"   fi}# 如果用户文件存在并且大小大于0就备份if [ -s $USER_FILE ]; then   mv $USER_FILE ${USER_FILE}-${DATE}.bak   echo_color green "$USER_FILE exist, rename ${USER_FILE}-${DATE}.bak"fiecho -e "User Password" >> $USER_FILEecho "----------------" >> $USER_FILEfor USER in user{1..10}; do   if ! id $USER &>/dev/null; then       PASS=$(echo $RANDOM |md5sum |cut -c 1-8)       useradd $USER       echo $PASS |passwd --stdin $USER &>/dev/null       echo -e "$USER $PASS" >> $USER_FILE       echo "$USER User create successful."   else       echo_color red "$USER User already exists!"   fidone

4、检查软件包是否安装

#!/bin/bashif rpm -q sysstat &>/dev/null; then   echo "sysstat is already installed."else   echo "sysstat is not installed!"fi

5、检查服务状态

#!/bin/bashPORT_C=$(ss -anu |grep -c 123)PS_C=$(ps -ef |grep ntpd |grep -vc grep)if [ $PORT_C -eq 0 -o $PS_C -eq 0 ]; then   echo "内容" | mail -s "主题" dst@example.comfi

6、检查主机存活状态

方法1：将错误IP放到数组里面判断是否ping失败三次#!/bin/bash  IP_LIST="192.168.18.1 192.168.1.1 192.168.18.2"for IP in $IP_LIST; do   NUM=1   while [ $NUM -le 3 ]; do       if ping -c 1 $IP > /dev/null; then           echo "$IP Ping is successful."           break       else           # echo "$IP Ping is failure $NUM"           FAIL_COUNT[$NUM]=$IP           let NUM++       fi   done   if [ ${#FAIL_COUNT[*]} -eq 3 ];then       echo "${FAIL_COUNT[1]} Ping is failure!"       unset FAIL_COUNT[*]   fidone  方法2：将错误次数放到FAIL_COUNT变量里面判断是否ping失败三次#!/bin/bash  IP_LIST="192.168.18.1 192.168.1.1 192.168.18.2"for IP in $IP_LIST; do   FAIL_COUNT=0   for ((i=1;ido       if ping -c 1 $IP >/dev/null; then           echo "$IP Ping is successful."           break       else           # echo "$IP Ping is failure $i"           let FAIL_COUNT++       fi   done   if [ $FAIL_COUNT -eq 3 ]; then       echo "$IP Ping is failure!"   fidone方法3：利用for循环将ping通就跳出循环继续，如果不跳出就会走到打印ping失败#!/bin/bashping_success_status() {   if ping -c 1 $IP >/dev/null; then       echo "$IP Ping is successful."       continue   fi}IP_LIST="192.168.18.1 192.168.1.1 192.168.18.2"for IP in $IP_LIST; do   ping_success_status   ping_success_status   ping_success_status   echo "$IP Ping is failure!"done

7、监控CPU、内存和硬盘利用率

1）CPU借助vmstat工具来分析CPU统计信息。#!/bin/bashDATE=$(date +%F" "%H:%M)IP=$(ifconfig eth0 |awk -F  [ :]+   /inet addr/{print $4} )  # 只支持CentOS6MAIL="example@mail.com"if ! which vmstat &>/dev/null; then   echo "vmstat command no found, Please install procps package."   exit 1fiUS=$(vmstat |awk  NR==3{print $13} )SY=$(vmstat |awk  NR==3{print $14} )IDLE=$(vmstat |awk  NR==3{print $15} )WAIT=$(vmstat |awk  NR==3{print $16} )USE=$(($US+$SY))if [ $USE -ge 50 ]; then   echo "   Date: $DATE   Host: $IP   Problem: CPU utilization $USE   " | mail -s "CPU Monitor" $MAILfi2）内存#!/bin/bashDATE=$(date +%F" "%H:%M)IP=$(ifconfig eth0 |awk -F  [ :]+   /inet addr/{print $4} )  MAIL="example@mail.com"TOTAL=$(free -m |awk  /Mem/{print $2} )USE=$(free -m |awk  /Mem/{print $3-$6-$7} )FREE=$(($TOTAL-$USE))# 内存小于1G发送报警邮件if [ $FREE -lt 1024 ]; then   echo "   Date: $DATE   Host: $IP   Problem: Total=$TOTAL,Use=$USE,Free=$FREE   " | mail -s "Memory Monitor" $MAILfi3）硬盘#!/bin/bashDATE=$(date +%F" "%H:%M)IP=$(ifconfig eth0 |awk -F  [ :]+   /inet addr/{print $4} )  MAIL="example@mail.com"TOTAL=$(fdisk -l |awk -F [: ]+   BEGIN{OFS="="}/^Disk /dev/{printf "%s=%sG,",$2,$3} )PART_USE=$(df -h |awk  BEGIN{OFS="="}/^/dev/{print $1,int($5),$6} )for i in $PART_USE; do   PART=$(echo $i |cut -d"=" -f1)   USE=$(echo $i |cut -d"=" -f2)   MOUNT=$(echo $i |cut -d"=" -f3)   if [ $USE -gt 80 ]; then       echo "       Date: $DATE       Host: $IP       Total: $TOTAL       Problem: $PART=$USE($MOUNT)       " | mail -s "Disk Monitor" $MAIL   fidone

8、批量主机磁盘利用率监控

前提监控端和被监控端SSH免交互登录或者密钥登录。写一个配置文件保存被监控主机SSH连接信息，文件内容格式：IP User Port#!/bin/bashHOST_INFO=host.infofor IP in $(awk  /^[^#]/{print $1}  $HOST_INFO); do   USER=$(awk -v ip=$IP  ip==$1{print $2}  $HOST_INFO)   PORT=$(awk -v ip=$IP  ip==$1{print $3}  $HOST_INFO)   TMP_FILE=/tmp/disk.tmp   ssh -p $PORT $USER@$IP  df -h  > $TMP_FILE   USE_RATE_LIST=$(awk  BEGIN{OFS="="}/^/dev/{print $1,int($5)}  $TMP_FILE)   for USE_RATE in $USE_RATE_LIST; do       PART_NAME=${USE_RATE%=*}       USE_RATE=${USE_RATE#*=}       if [ $USE_RATE -ge 80 ]; then           echo "Warning: $PART_NAME Partition usage $USE_RATE%!"       fi   donedone

9、检查网站可用性

1）检查URL可用性方法1：check_url() {   HTTP_CODE=$(curl -o /dev/null --connect-timeout 3 -s -w "%{http_code}" $1)   if [ $HTTP_CODE -ne 200 ]; then       echo "Warning: $1 Access failure!"   fi}方法2：check_url() {if ! wget -T 10 --tries=1 --spider $1 >/dev/null 2>&1; then  #-T超时时间，--tries尝试1次，--spider爬虫模式       echo "Warning: $1 Access failure!"   fi}使用方法：check_url www.baidu.com2）判断三次URL可用性思路与上面检查主机存活状态一样。方法1：利用循环技巧，如果成功就跳出当前循环，否则执行到最后一行#!/bin/bash  check_url() {   HTTP_CODE=$(curl -o /dev/null --connect-timeout 3 -s -w "%{http_code}" $1)   if [ $HTTP_CODE -eq 200 ]; then       continue   fi}URL_LIST="www.baidu.com www.agasgf.com"for URL in $URL_LIST; do   check_url $URL   check_url $URL   check_url $URL   echo "Warning: $URL Access failure!"done  方法2：错误次数保存到变量#!/bin/bash  URL_LIST="www.baidu.com www.agasgf.com"for URL in $URL_LIST; do   FAIL_COUNT=0   for ((i=1;ido       HTTP_CODE=$(curl -o /dev/null --connect-timeout 3 -s -w "%{http_code}" $URL)       if [ $HTTP_CODE -ne 200 ]; then           let FAIL_COUNT++       else           break       fi   done   if [ $FAIL_COUNT -eq 3 ]; then       echo "Warning: $URL Access failure!"   fidone  方法3：错误次数保存到数组#!/bin/bash  URL_LIST="www.baidu.com www.agasgf.com"for URL in $URL_LIST; do   NUM=1   while [ $NUM -le 3 ]; do       HTTP_CODE=$(curl -o /dev/null --connect-timeout 3 -s -w "%{http_code}" $URL)       if [ $HTTP_CODE -ne 200 ]; then           FAIL_COUNT[$NUM]=$IP  #创建数组，以$NUM下标，$IP元素           let NUM++       else           break       fi   done   if [ ${#FAIL_COUNT[*]} -eq 3 ]; then       echo "Warning: $URL Access failure!"       unset FAIL_COUNT[*]    #清空数组   fidone

10、检查MySQL主从同步状态

#!/bin/bash  USER=bakPASSWD=123456IO_SQL_STATUS=$(mysql -u$USER -p$PASSWD -e  show slave statusG  |awk -F:  /Slave_.*_Running/{gsub(": ",":");print $0} )  #gsub去除冒号后面的空格for i in $IO_SQL_STATUS; do   THREAD_STATUS_NAME=${i%:*}   THREAD_STATUS=${i#*:}   if [ "$THREAD_STATUS" != "Yes" ]; then       echo "Error: MySQL Master-Slave $THREAD_STATUS_NAME status is $THREAD_STATUS!"   fidone