shell脚本上

作者: 与诗小睡 | 来源:发表于2020-12-09 22:21 被阅读0次

| 对于初学者而言，因为没有实战经验，写不出来Shell 脚本很正常，如果工作了几年的运维老年还是写不出来，那就是没主动找需求，缺乏练习，缺乏经验。针对以上问题，总结了30个生产环境中经典的Shell 脚本，通过这些需求案例，希望能帮助大家提升Shell编写思路，掌握编写技巧。 |

先了解下编写Shell过程中注意事项：

<pre style="margin: 0px; padding: 0px; overflow: auto; white-space: pre-wrap; color: rgb(51, 51, 51); font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;">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。
</pre>

1、获取随机字符串或数字

<pre style="margin: 0px; padding: 0px; overflow: auto; white-space: pre-wrap; color: rgb(51, 51, 51); font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;">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
</pre>

2、定义一个颜色输出字符串函数

<pre style="margin: 0px; padding: 0px; overflow: auto; white-space: pre-wrap; color: rgb(51, 51, 51); font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;">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。
</pre>

3、批量创建用户

<pre style="margin: 0px; padding: 0px; overflow: auto; white-space: pre-wrap; color: rgb(51, 51, 51); font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;">#!/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}- ${DATE}.bak" fi echo -e "User Password" >>$ 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
</pre>

4、检查软件包是否安装

<pre style="margin: 0px; padding: 0px; overflow: auto; white-space: pre-wrap; color: rgb(51, 51, 51); font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;">#!/bin/bash
if rpm -q sysstat &>/dev/null; then
echo "sysstat is already installed."
else
echo "sysstat is not installed!"
fi
</pre>

5、检查服务状态

<pre style="margin: 0px; padding: 0px; overflow: auto; white-space: pre-wrap; color: rgb(51, 51, 51); font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;">#!/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" dst@example.com
fi
</pre>

6、检查主机存活状态

<pre style="margin: 0px; padding: 0px; overflow: auto; white-space: pre-wrap; color: rgb(51, 51, 51); font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;">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
</pre>

7、监控CPU、内存和硬盘利用率

<pre style="margin: 0px; padding: 0px; overflow: auto; white-space: pre-wrap; color: rgb(51, 51, 51); font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;">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 $4} ) # 只支持[CentOS](https://www.linuxprobe.com/ "centos")6 MAIL="example@mail.com" if ! which vmstat &>/dev/null; then echo "vmstat command no found, Please install procps package." exit 1 fi US=$ (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 $4} ) MAIL="example@mail.com" TOTAL=$ (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" $MAIL
fi

3）硬盘

!/bin/bash

DATE= $(date +%F" "%H:%M) IP=$ (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
fi
done
</pre>

8、批量主机磁盘利用率监控

<pre style="margin: 0px; padding: 0px; overflow: auto; white-space: pre-wrap; color: rgb(51, 51, 51); font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;">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 $USER@$ 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
done
done
</pre>

9、检查网站可用性

<pre style="margin: 0px; padding: 0px; overflow: auto; white-space: pre-wrap; color: rgb(51, 51, 51); font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;">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
</pre>

10、检查MySQL主从同步状态

<pre style="margin: 0px; padding: 0px; overflow: auto; white-space: pre-wrap; color: rgb(51, 51, 51); font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;">#!/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
</pre>

动手练一练，让你的Shell功底上升一个段位！

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shell脚本上

echo $RANDOM |md5sum |cut -c 1-8

openssl rand -base64 4

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

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

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

date +%N |cut -c 1-8

如果用户文件存在并且大小大于0就备份

!/bin/bash

!/bin/bash

!/bin/bash

!/bin/bash

!/bin/bash

内存小于1G发送报警邮件

!/bin/bash

!/bin/bash

-T超时时间，--tries尝试1次，--spider爬虫模式

!/bin/bash

!/bin/bash

!/bin/bash

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