30个经典shell脚本上

注:转自https://weibo.com/linuxprobe?topnav=1&wvr=6&topsug=1&is_hot=1(刘遄老师的Linux就该这样学)

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 1-8

471b94f2

方法2:

# openssl rand -base64 4

vg3BEg==

方法3:

# cat /proc/sys/kernel/random/uuid |cut -c 1-8

ed9e032c

获取随机8位数字:

方法1:

# echo $RANDOM |cksum |cut -c 1-8

23648321

方法2:

# openssl rand -base64 4 |cksum |cut -c 1-8

38571131

方法3:

# date +%N |cut -c 1-8

69024815

cksum: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/bash

DATE=$(date +%F_%T)

USER_FILE=user.txt

echo_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"

fi

echo -e "UserPassword" >> $USER_FILE

echo "----------------" >> $USER_FILE

for 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!"

fi

done

4、检查软件包是否安装

#!/bin/bash

if 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/bash

PORT_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" [email protected]

fi

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[*]

fi

done

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;i< =3;i++)); do

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!"

fi

done

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/bash

ping_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/bash

DATE=$(date +%F" "%H:%M)

IP=$(ifconfig eth0 |awk -F [ :]+ /inet addr/{print $4} ) # 只支持CentOS6

MAIL="[email protected]"

if ! which vmstat &>/dev/null; then

echo "vmstat command no found, Please install procps package."

exit 1

fi

US=$(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" $MAIL

fi

2)内存

#!/bin/bash

DATE=$(date +%F" "%H:%M)

IP=$(ifconfig eth0 |awk -F [ :]+ /inet addr/{print $4} )

MAIL="[email protected]"

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" $MAIL

fi

3)硬盘

#!/bin/bash

DATE=$(date +%F" "%H:%M)

IP=$(ifconfig eth0 |awk -F [ :]+ /inet addr/{print $4} )

MAIL="[email protected]"

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

fi

done

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/bash

HOST_INFO=host.info

for 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 $PORT [email protected]$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

done

done

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.com

?

2)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;i< =3;i++)); do

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!"

fi

done

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

fi

done

10、检查MySQL主从同步状态

#!/bin/bash

USER=bak

PASSWD=123456

IO_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!"

fi

done

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