30个经典shell脚本上

Posted 2022-10-27 zjz20

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 user1..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" [e-mail]

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="[e-mail]"

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

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

exit 1

fi

US=$(vmstat |awk NR==3print $13 )

SY=$(vmstat |awk NR==3print $14 )

IDLE=$(vmstat |awk NR==3print $15 )

WAIT=$(vmstat |awk NR==3print $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="[e-mail]"

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="[e-mail]"

TOTAL=$(fdisk -l |awk -F [: ]+ BEGINOFS="="/^Disk /dev/printf "%s=%sG,",$2,$3 )

PART_USE=$(df -h |awk BEGINOFS="="/^/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==$1print $2 $HOST_INFO)

PORT=$(awk -v ip=$IP ip==$1print $3 $HOST_INFO)

TMP_FILE=/tmp/disk.tmp

ssh -p $PORT $USER@$IP df -h > $TMP_FILE

USE_RATE_LIST=$(awk BEGINOFS="="/^/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