https://www.cnblogs.com/linuxprobe/p/11518761.html

30個(gè)關(guān)于Shell腳本的經(jīng)典案例（上）

| 對于初學(xué)者而言，因?yàn)闆]有實(shí)戰(zhàn)經(jīng)驗(yàn)，寫不出來Shell 腳本很正常，如果工作了幾年的運(yùn)維老年還是寫不出來，那就是沒主動(dòng)找需求，缺乏練習(xí)，缺乏經(jīng)驗(yàn)。針對以上問題，總結(jié)了30個(gè)生產(chǎn)環(huán)境中經(jīng)典的Shell 腳本，通過這些需求案例，希望能幫助大家提升Shell編寫思路，掌握編寫技巧。 |

先了解下編寫Shell過程中注意事項(xiàng)：

<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word;">開頭加解釋器：#!/bin/bash
語法縮進(jìn)，使用四個(gè)空格；多加注釋說明。
命名建議規(guī)則：變量名大寫、局部變量小寫，函數(shù)名小寫，名字體現(xiàn)出實(shí)際作用。
默認(rèn)變量是全局的，在函數(shù)中變量local指定為局部變量，避免污染其他作用域。
有兩個(gè)命令能幫助我調(diào)試腳本：set -e 遇到執(zhí)行非0時(shí)退出腳本，set-x 打印執(zhí)行過程。
寫腳本一定先測試再到生產(chǎn)上。
</pre>

1、獲取隨機(jī)字符串或數(shù)字

<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word;">獲取隨機(jī)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

獲取隨機(jī)8位數(shù)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效驗(yàn)和統(tǒng)計(jì)字節(jié)
</pre>

2、定義一個(gè)顏色輸出字符串函數(shù)

<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word;">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關(guān)鍵字定義一個(gè)函數(shù)，可加或不加。
</pre>

3、批量創(chuàng)建用戶

<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word;">#!/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
}

如果用戶文件存在并且大小大于0就備份

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、檢查軟件包是否安裝

<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word;">#!/bin/bash
if rpm -q sysstat &>/dev/null; then
echo "sysstat is already installed."
else
echo "sysstat is not installed!"
fi
</pre>

5、檢查服務(wù)狀態(tài)

<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word;">#!/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 "內(nèi)容" | mail -s "主題" dst@example.com
fi
</pre>

6、檢查主機(jī)存活狀態(tài)

<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word;">方法1：將錯(cuò)誤IP放到數(shù)組里面判斷是否ping失敗三次

!/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：將錯(cuò)誤次數(shù)放到FAIL_COUNT變量里面判斷是否ping失敗三次

!/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循環(huán)將ping通就跳出循環(huán)繼續(xù)，如果不跳出就會(huì)走到打印ping失敗

!/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、監(jiān)控CPU、內(nèi)存和硬盤利用率

<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word;">1）CPU
借助vmstat工具來分析CPU統(tǒng)計(jì)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）內(nèi)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))

內(nèi)存小于1G發(fā)送報(bào)警郵件

if [ $FREE -lt 1024 ]; then echo " Date:$ DATE
Host: $IP Problem: Total=$ TOTAL,Use= $USE,Free=$ FREE
" | mail -s "Memory Monitor" $MAIL
fi

3）硬盤

!/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、批量主機(jī)磁盤利用率監(jiān)控

<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word;">前提監(jiān)控端和被監(jiān)控端SSH免交互登錄或者密鑰登錄。

寫一個(gè)配置文件保存被監(jiān)控主機(jī)SSH連接信息，文件內(nèi)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、檢查網(wǎng)站可用性

<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word;">1）檢查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超時(shí)時(shí)間，--tries嘗試1次，--spider爬蟲模式

    echo "Warning: $1 Access failure!"
fi

}

使用方法：check_url www.baidu.com

2）判斷三次URL可用性
思路與上面檢查主機(jī)存活狀態(tài)一樣。

方法1：利用循環(huán)技巧，如果成功就跳出當(dāng)前循環(huán)，否則執(zhí)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：錯(cuò)誤次數(shù)保存到變量

!/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：錯(cuò)誤次數(shù)保存到數(shù)組

!/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]= $IP #創(chuàng)建數(shù)組，以$ NUM下標(biāo)， $IP元素 let NUM++ else break fi done if [$ {#FAIL_COUNT[]} -eq 3 ]; then
echo "Warning: $URL Access failure!"
unset FAIL_COUNT[] #清空數(shù)組
fi
done
</pre>

10、檢查MySQL主從同步狀態(tài)

<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word;">#!/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去除冒號后面的空格
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>

動(dòng)手練一練，讓你的Shell功底上升一個(gè)段位！

本文目錄

<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word; 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-style: initial; text-decoration-color: initial;">11、iptables自動(dòng)屏蔽訪問網(wǎng)站頻繁的IP
12、判斷用戶輸入的是否為IP地址
13、判斷用戶輸入的是否為數(shù)字
14、給定目錄找出包含關(guān)鍵字的文件
15、監(jiān)控目錄，將新創(chuàng)建的文件名追加到日志中
16、給用戶提供多個(gè)網(wǎng)卡選擇
17、查看網(wǎng)卡實(shí)時(shí)流量
18、MySQL數(shù)據(jù)庫備份
19、Nginx服務(wù)管理腳本
20、用戶根據(jù)菜單選擇要連接的Linux主機(jī)
</pre>

11、iptables自動(dòng)屏蔽訪問網(wǎng)站頻繁的IP

1）屏蔽每分鐘訪問超過200的IP

方法1：根據(jù)訪問日志（Nginx為例）

!/bin/bash

DATE= $(date +%d/%b/%Y:%H:%M) ABNORMAL_IP=$ (tail -n5000 access.log |grep $DATE |awk '{a[$ 1]++}END{for(i in a)if(a[i]>100)print i}')

先tail防止文件過大，讀取慢，數(shù)字可調(diào)整每分鐘最大的訪問量。awk不能直接過濾日志，因?yàn)榘厥庾址?/h1>
for IP in $ABNORMAL_IP; do if [$ (iptables -vnL |grep -c " $IP") -eq 0 ]; then iptables -I INPUT -s$ IP -j DROP
fi
done
方法2：通過TCP建立的連接

!/bin/bash

ABNORMAL_IP= $(netstat -an |awk '$ 4~/:80 $/ &&$ 6~/ESTABLISHED/{gsub(/:[0-9]+/,"", $5);{a[$ 5]++}}END{for(i in a)if(a[i]>100)print i}')

gsub是將第五列（客戶端IP）的冒號和端口去掉

for IP in $ABNORMAL_IP; do if [$ (iptables -vnL |grep -c " $IP") -eq 0 ]; then iptables -I INPUT -s$ IP -j DROP
fi
done

2）屏蔽每分鐘SSH嘗試登錄超過10次的IP

方法1：通過lastb獲取登錄狀態(tài):

!/bin/bash

DATE= $(date +"%a %b %e %H:%M") #星期月天時(shí)分 %e單數(shù)字時(shí)顯示7，而%d顯示07 ABNORMAL_IP=$ (lastb |grep " $DATE" |awk '{a[$ 3]++}END{for(i in a)if(a[i]>10)print i}')
for IP in $ABNORMAL_IP; do if [$ (iptables -vnL |grep -c " $IP") -eq 0 ]; then iptables -I INPUT -s$ IP -j DROP
fi
done
方法2：通過日志獲取登錄狀態(tài)

!/bin/bash

DATE= $(date +"%b %d %H") ABNORMAL_IP="$ (tail -n10000 /var/log/auth.log |grep " $DATE" |awk '/Failed/{a[$ (NF-3)]++}END{for(i in a)if(a[i]>5)print i}')"
for IP in $ABNORMAL_IP; do if [$ (iptables -vnL |grep -c " $IP") -eq 0 ]; then iptables -A INPUT -s$ IP -j DROP
echo " $(date +"%F %T") - iptables -A INPUT -s$ IP -j DROP" >>~/ssh-login-limit.log
fi
done
</pre>

12、判斷用戶輸入的是否為IP地址

!/bin/bash

function check_ip(){
IP= $1 VALID_CHECK=$ (echo $IP|awk -F. '$ 1< =255&& $2<=255&&$ 3<=255&& $4<=255{print "yes"}') if echo$ IP|grep -E "^[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3} $">/dev/null; then if [$ VALID_CHECK == "yes" ]; then
echo " $IP available." else echo "$ IP not available!"
fi
else
echo "Format error!"
fi
}
check_ip 192.168.1.1
check_ip 256.1.1.1
方法2：

!/bin/bash

function check_ip(){
IP= $1 if [[$ IP =~ ^[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3} $]]; then FIELD1=$ (echo $IP|cut -d. -f1) FIELD2=$ (echo $IP|cut -d. -f2) FIELD3=$ (echo $IP|cut -d. -f3) FIELD4=$ (echo $IP|cut -d. -f4) if [$ FIELD1 -le 255 -a $FIELD2 -le 255 -a$ FIELD3 -le 255 -a $FIELD4 -le 255 ]; then echo "$ IP available."
else
echo "$IP not available!"
fi
else
echo "Format error!"
fi
}
check_ip 192.168.1.1
check_ip 256.1.1.1
增加版：

加個(gè)死循環(huán)，如果IP可用就退出，不可用提示繼續(xù)輸入，并使用awk判斷。

!/bin/bash

13、判斷用戶輸入的是否為數(shù)字

!/bin/bash

if [[ $1 =~ ^[0-9]+$ ]]; then
echo "Is Number."
else
echo "No Number."
fi
方法2：

!/bin/bash

if [ $1 -gt 0 ] 2>/dev/null; then
echo "Is Number."
else
echo "No Number."
fi
方法3：

!/bin/bash

echo $1 |awk '{print$ 0~/^[0-9]+ $/?"Is Number.":"No Number."}' #三目運(yùn)算符 12.14 找出包含關(guān)鍵字的文件 DIR=$ 1
KEY= $2 for FILE in$ (find $DIR -type f); do if grep$ KEY $FILE &>/dev/null; then echo "-->$ FILE"
fi
done
</pre>

14、給定目錄找出包含關(guān)鍵字的文件

15、監(jiān)控目錄，將新創(chuàng)建的文件名追加到日志中

需先安裝inotify-tools軟件包。

!/bin/bash

MON_DIR=/opt
inotifywait -mq --format %f -e create $MON_DIR |\ while read files; do echo$ files >> test.log
done
</pre>

16、給用戶提供多個(gè)網(wǎng)卡選擇

!/bin/bash

17、查看網(wǎng)卡實(shí)時(shí)流量

!/bin/bash

Description: Only CentOS6

traffic_unit_conv() {
local traffic= $1 if [$ traffic -gt 1024000 ]; then
printf "%.1f%s" " $(($ traffic/1024/1024))" "MB/s"
elif [ $traffic -lt 1024000 ]; then printf "%.1f%s" "$ (( $traffic/1024))" "KB/s" fi } NIC=$ 1
echo -e " In ------ Out"
while true; do
OLD_IN= $(awk -F'[: ]+' '$ 0~"' $NIC'"{print$ 3}' /proc/net/dev)
OLD_OUT= $(awk -F'[: ]+' '$ 0~"' $NIC'"{print$ 11}' /proc/net/dev)
sleep 1
NEW_IN= $(awk -F'[: ]+' '$ 0~"' $NIC'"{print$ 3}' /proc/net/dev)
NEW_OUT= $(awk -F'[: ]+' '$ 0~"' $NIC'"{print$ 11}' /proc/net/dev)
IN= $(($ NEW_IN- $OLD_IN)) OUT=$ (( $NEW_OUT-$ OLD_OUT))
echo " $(traffic_unit_conv$ IN) $(traffic_unit_conv$ OUT)"
sleep 1
done
使用：./traffic.sh eth0
</pre>

18、MySQL數(shù)據(jù)庫備份

<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word; 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-style: initial; text-decoration-color: initial;">#!/bin/bash
DATE= $(date +%F_%H-%M-%S) HOST=192.168.1.120 DB=test USER=bak PASS=123456 MAIL="zhangsan@example.com lisi@example.com" BACKUP_DIR=/data/db_backup SQL_FILE=$ {DB}full $DATE.sql BAK_FILE=$ {DB}full $DATE.zip cd$ BACKUP_DIR
if mysqldump -h $HOST -u$ USER -p $PASS --single-transaction --routines --triggers -B$ DB > $SQL_FILE; then zip$ BAK_FILE $SQL_FILE && rm -f$ SQL_FILE
if [ ! -s $BAK_FILE ]; then echo "$ DATE 內(nèi)容" | mail -s "主題" $MAIL fi else echo "$ DATE 內(nèi)容" | mail -s "主題" $MAIL fi find$ BACKUP_DIR -name '*.zip' -ctime +14 -exec rm {} ;
</pre>

19、Nginx服務(wù)管理腳本

!/bin/bash

Description: Only support RedHat system

. /etc/init.d/functions
WORD_DIR=/usr/local/nginx
DAEMON= $WORD_DIR/sbin/nginx CONF=$ WORD_DIR/conf/nginx.conf
NAME=nginx
PID= $(awk -F'[; ]+' '/^[^#]/{if($ 0~/pid;/)print $2}'$ CONF)
if [ -z " $PID" ]; then PID=$ WORD_DIR/logs/nginx.pid
else
PID= $WORD_DIR/$ PID
fi
stop() {
$DAEMON -s stop sleep 1 [ ! -f$ PID ] && action "* Stopping $NAME" /bin/true || action "* Stopping$ NAME" /bin/false
}
start() {
$DAEMON sleep 1 [ -f$ PID ] && action "* Starting $NAME" /bin/true || action "* Starting$ NAME" /bin/false
}
reload() {
$DAEMON -s reload } test_config() {$ DAEMON -t
}
case " $1" in start) if [ ! -f$ PID ]; then
start
else
echo " $NAME is running..." exit 0 fi ;; stop) if [ -f$ PID ]; then
stop
else
echo " $NAME not running!" exit 0 fi ;; restart) if [ ! -f$ PID ]; then
echo " $NAME not running!" start else stop start fi ;; reload) reload ;; testconfig) test_config ;; status) [ -f$ PID ] && echo " $NAME is running..." || echo "$ NAME not running!"
;;
*)
echo "Usage: $0 {start|stop|restart|reload|testconfig|status}"
exit 3
;;
esac</pre>

https://article.pchome.net/content-2100027.html
http://www.51cto.com/it/news/2019/0909/14338.html
https://www.linuxprobe.com/books

20、用戶根據(jù)菜單選擇要連接的Linux主機(jī)

cat host.txt

Web 192.168.1.10 root 22
DB 192.168.1.11 root 22
內(nèi)容格式：主機(jī)名 IP User Port

!/bin/bash

PS3="Please input number: "
HOST_FILE=host.txt
while true; do
select NAME in $(awk '{print$ 1}' $HOST_FILE) quit; do [$ {NAME:=empty} == "quit" ] && exit 0
IP= $(awk -v NAME=$ {NAME} ' $1==NAME{print$ 2}' $HOST_FILE) USER=$ (awk -v NAME= ${NAME} '$ 1==NAME{print $3}'$ HOST_FILE)
PORT= $(awk -v NAME=$ {NAME} ' $1==NAME{print$ 4}' $HOST_FILE) if [$ IP ]; then
echo "Name: $NAME, IP:$ IP"
ssh -o StrictHostKeyChecking=no -p $PORT -i id_rsa$ USER@$IP # 密鑰免交互登錄
break
else
echo "Input error, Please enter again!"
break
fi
done
done</pre>

本文目錄

<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word; 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-style: initial; text-decoration-color: initial;">21、從FTP服務(wù)器下載文件
22、連續(xù)輸入5個(gè)100以內(nèi)的數(shù)字，統(tǒng)計(jì)和、最小和最大
23、將結(jié)果分別賦值給變量
24、批量修改文件名
25、統(tǒng)計(jì)當(dāng)前目錄中以.html結(jié)尾的文件總大
26、掃描主機(jī)端口狀態(tài)
27、Expect實(shí)現(xiàn)SSH免交互執(zhí)行命令
28、批量修改服務(wù)器用戶密碼
29、打印乘法口訣
30、getopts工具完善腳本命令行參數(shù)
</pre>

21、從FTP服務(wù)器下載文件

<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word; 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-style: initial; text-decoration-color: initial;">#!/bin/bash
if [ $# -ne 1 ]; then echo "Usage:$ 0 filename"
fi
dir= $(dirname$ 1)
file= $(basename$ 1)
ftp -n -v << EOF # -n 自動(dòng)登錄
open 192.168.1.10 # ftp服務(wù)器
user admin password
binary # 設(shè)置ftp傳輸模式為二進(jìn)制，避免MD5值不同或.tar.gz壓縮包格式錯(cuò)誤
cd $dir get "$ file"
EOF
</pre>

22、連續(xù)輸入5個(gè)100以內(nèi)的數(shù)字，統(tǒng)計(jì)和、最小和最大

<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word; 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-style: initial; text-decoration-color: initial;">#!/bin/bash
COUNT=1
SUM=0
MIN=0
MAX=100
while [ $COUNT -le 5 ]; do read -p "請輸入1-10個(gè)整數(shù)：" INT if [[ !$ INT =~ ^[0-9]+ $]]; then echo "輸入必須是整數(shù)！" exit 1 elif [[$ INT -gt 100 ]]; then
echo "輸入必須是100以內(nèi)！"
exit 1
fi
SUM= $(($ SUM+ $INT)) [$ MIN -lt $INT ] && MIN=$ INT
[ $MAX -gt$ INT ] && MAX= $INT let COUNT++ done echo "SUM:$ SUM"
echo "MIN: $MIN" echo "MAX:$ MAX"
</pre>

30個(gè)關(guān)于Shell腳本的經(jīng)典案例（下）30個(gè)關(guān)于Shell腳本的經(jīng)典案例（下）

23、將結(jié)果分別賦值給變量

方法1：

for i in $(echo "4 5 6"); do eval a$ i= $i done echo$ a4 $a5$ a6
方法2：將位置參數(shù)192.168.1.1{1,2}拆分為到每個(gè)變量

num=0
for i in $(eval echo$ *);do #eval將{1,2}分解為1 2
let num+=1
eval node ${num}="$ i"
done
echo $node1$ node2 $node3

bash a.sh 192.168.1.1{1,2}

192.168.1.11 192.168.1.12
方法3：

arr=(4 5 6)
INDEX1= $(echo$ {arr[0]})
INDEX2= $(echo$ {arr[1]})
INDEX3= $(echo$ {arr[2]})
</pre>

24、批量修改文件名

touch article_{1..3}.html

ls

article_1.html article_2.html article_3.html
目的：把a(bǔ)rticle改為bbs

方法1：

for file in $(ls *html); do mv$ file bbs_ ${file#*_} # mv$ file $(echo$ file |sed -r 's/.(_.)/bbs\1/')
# mv $file$ (echo $file |echo bbs_$ (cut -d_ -f2)
done
方法2：

for file in $(find . -maxdepth 1 -name "*html"); do mv$ file bbs_${file#*_}
done
方法3：

rename article bbs *.html

</pre>

25、統(tǒng)計(jì)當(dāng)前目錄中以.html結(jié)尾的文件總大

find . -name "*.html" -exec du -k {} ; |awk '{sum+=$1}END{print sum}'

方法2：

for size in $(ls -l *.html |awk '{print$ 5}'); do
sum= $(($ sum+ $size)) done echo$ sum
</pre>

26、掃描主機(jī)端口狀態(tài)

27、Expect實(shí)現(xiàn)SSH免交互執(zhí)行命令

需先安裝expect軟件包。

方法1：EOF標(biāo)準(zhǔn)輸出作為expect標(biāo)準(zhǔn)輸入

!/bin/bash

USER=root
PASS=123.com
IP=192.168.1.120
expect << EOF
set timeout 30
spawn ssh $USER@$ IP
expect {
"(yes/no)" {send "yes\r"; exp_continue}
"password:" {send " $PASS\r"} } expect "$ USER@" {send " $1\r"} expect "$ USER@" {send "exit\r"}
expect eof
EOF
方法2：

!/bin/bash

USER=root
PASS=123.com
IP=192.168.1.120
expect -c "
spawn ssh $USER@$ IP
expect {
"(yes/no)" {send "yes\r"; exp_continue}
"password:" {send " $PASS\r\"; exp_continue} \"$ USER@*" {send "df -h\r exit\r"; exp_continue}
}"
方法3：將expect腳本獨(dú)立出來

登錄腳本：

cat login.exp

!/usr/bin/expect

set ip [lindex $argv 0] set user [lindex$ argv 1]
set passwd [lindex $argv 2] set cmd [lindex$ argv 3]
if { $argc != 4 } { puts "Usage: expect login.exp ip user passwd" exit 1 } set timeout 30 spawn ssh$ user@ $ip expect { "(yes/no)" {send "yes\r"; exp_continue} "password:" {send "$ passwd\r"}
}
expect " $user@*" {send "$ cmd\r"}
expect "$user@*" {send "exit\r"}
expect eof
執(zhí)行命令腳本：寫個(gè)循環(huán)可以批量操作多臺服務(wù)器

!/bin/bash

HOST_INFO=user_info.txt
for ip in $(awk '{print$ 1}' $HOST_INFO) do user=$ (awk -v I=" $ip" 'I==$ 1{print $2}'$ HOST_INFO)
pass= $(awk -v I="$ ip" 'I== $1{print$ 3}' $HOST_INFO) expect login.exp$ ip $user$ pass $1
done
Linux主機(jī)SSH連接信息：

cat user_info.txt

192.168.1.120 root 123456
</pre>

28、批量修改服務(wù)器用戶密碼

cat old_pass.txt

192.168.18.217 root 123456 22
192.168.18.218 root 123456 22
內(nèi)容格式：IP User Password Port

SSH遠(yuǎn)程修改密碼腳本：新密碼隨機(jī)生成
https://www.linuxprobe.com/books

!/bin/bash

OLD_INFO=old_pass.txt
NEW_INFO=new_pass.txt
for IP in $(awk '/^[^#]/{print$ 1}' $OLD_INFO); do USER=$ (awk -v I= $IP 'I==$ 1{print $2}'$ OLD_INFO)
PASS= $(awk -v I=$ IP 'I== $1{print$ 3}' $OLD_INFO) PORT=$ (awk -v I= $IP 'I==$ 1{print $4}'$ OLD_INFO)
NEW_PASS= $(mkpasswd -l 8) # 隨機(jī)密碼 echo "$ IP $USER$ NEW_PASS $PORT" >>$ NEW_INFO
expect -c "
spawn ssh -p $PORT$ USER@ $IP set timeout 2 expect { \"(yes/no)\" {send \"yes\r\";exp_continue} \"password:\" {send \"$ PASS\r";exp_continue}
" $USER@*\" {send \"echo \'$ NEW_PASS' |passwd --stdin $USER\r exit\r";exp_continue}
}"
done
生成新密碼文件：

cat new_pass.txt

192.168.18.217 root n8wX3mU% 22
192.168.18.218 root c87;ZnnL 22
</pre>

29、打印乘法口訣

awk 'BEGIN{for(n=0;n++<9;){for(i=0;i++<n;)printf i"x"n"="i*n" ";print ""}}'

方法2：

for ((i=1;i<=9;i++)); do
for ((j=1;j<=i;j++)); do
result= $(($ i $j)) echo -n "$ j $i=$ result "
done
echo
done
</pre>

30、getopts工具完善腳本命令行參數(shù)

命令格式：getopts optstring name [arg]

初次使用你要注意這幾點(diǎn)：

腳本位置參數(shù)會(huì)與optstring中的單個(gè)字母逐個(gè)匹配，如果匹配到就賦值給name，否則賦值name為問號；

optstring中單個(gè)字母是一個(gè)選項(xiàng)，如果字母后面加冒號，表示該選項(xiàng)后面帶參數(shù)，參數(shù)值并會(huì)賦值給OPTARG變量；

optstring中第一個(gè)是冒號，表示屏蔽系統(tǒng)錯(cuò)誤（test.sh: illegal option -- h）；

允許把選項(xiàng)放一起，例如-ab

下面寫一個(gè)打印文件指定行的簡單例子，引導(dǎo)你思路：

!/bin/bash

while getopts :f:n: option; do
case $option in f) FILE=$ OPTARG
[ ! -f $FILE ] && echo "$ FILE File not exist!" && exit
;;
n)
sed -n " ${OPTARG}p"$ FILE
;;
?)
echo "Usage: $0 -f -n "
echo "-f, --file specified file"
echo "-n, --line-number print specified line"
exit 1
;;
esac
done
</pre>

30個(gè)關(guān)于Shell腳本的經(jīng)典案例（下）30個(gè)關(guān)于Shell腳本的經(jīng)典案例（下）

根據(jù)工作經(jīng)驗(yàn)總結(jié)的30個(gè)Shell腳本案例至此完結(jié)，都還是比較實(shí)用的，面試筆試題也經(jīng)常會(huì)出。希望朋友們多動(dòng)手練一練，讓你的Shell功底上升一個(gè)段位！

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（轉(zhuǎn)）30個(gè)關(guān)于Shell腳本的經(jīng)典案例

30個(gè)關(guān)于Shell腳本的經(jīng)典案例（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

如果用戶文件存在并且大小大于0就備份

!/bin/bash

!/bin/bash

!/bin/bash

!/bin/bash

!/bin/bash

內(nèi)存小于1G發(fā)送報(bào)警郵件

!/bin/bash

!/bin/bash

-T超時(shí)時(shí)間，--tries嘗試1次，--spider爬蟲模式

!/bin/bash

!/bin/bash

!/bin/bash

!/bin/bash

先tail防止文件過大，讀取慢，數(shù)字可調(diào)整每分鐘最大的訪問量。awk不能直接過濾日志，因?yàn)榘厥庾址?/h1> for IP in (iptables -vnL |grep -c "IP -j DROP fi done 方法2：通過TCP建立的連接

!/bin/bash

gsub是將第五列（客戶端IP）的冒號和端口去掉

!/bin/bash

!/bin/bash

!/bin/bash

!/bin/bash

!/bin/bash

!/bin/bash

!/bin/bash

!/bin/bash

!/bin/bash

!/bin/bash

!/bin/bash

Description: Only CentOS6

!/bin/bash

Description: Only support RedHat system

cat host.txt

!/bin/bash

bash a.sh 192.168.1.1{1,2}

touch article_{1..3}.html

ls

rename article bbs *.html

find . -name "*.html" -exec du -k {} ; |awk '{sum+=$1}END{print sum}'

!/bin/bash

!/bin/bash

cat login.exp

!/usr/bin/expect

!/bin/bash

cat user_info.txt

cat old_pass.txt

!/bin/bash

cat new_pass.txt

awk 'BEGIN{for(n=0;n++<9;){for(i=0;i++<n;)printf i"x"n"="i*n" ";print ""}}'

!/bin/bash

友情鏈接更多精彩內(nèi)容

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-T超時(shí)時(shí)間，--tries嘗試1次，--spider爬蟲模式