超实用！18 个开箱即用的 Shell 脚本，拿好了~

刺骨的言语ヽ痛彻心扉 2023-01-19 12:57 6阅读 0赞

1、[检测两台服务器指定目录下的文件一致][Link 1]  
\#!/bin/bash  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
检测两台服务器指定目录下的文件一致性  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
\#通过对比两台服务器上文件的md5值，达到检测一致性的目的  
dir=/data/web  
b\_ip=192.168.88.10  
\#将指定目录下的文件全部遍历出来并作为md5sum命令的参数，进而得到所有文件的md5值，并写入到指定文件中  
find $dir -type f|xargs md5sum > /tmp/md5\_a.txt  
ssh $b\_ip “find $dir -type f|xargs md5sum > /tmp/md5\_b.txt”  
scp KaTeX parse error: Expected 'EOF', got '\#' at position 26: …md5\_b.txt /tmp \#̲将文件名作为遍历对象进行一一比…f" /tmp/md5\_b.txt  
then  
md5\_a=`grep -w "$f" /tmp/md5_a.txt|awk '{print 1}'`  
md5\_b=`grep -w "$f" /tmp/md5_b.txt|awk '{print 1}'`  
\#当文件存在时，如果md5值不一致则输出文件改变的结果  
if \[ $md5\_a !=  m d 5 b \] t h e n e c h o " md5\_b \]then echo " md5b\]thenecho"f changed."  
fi  
else  
echo “$f deleted.”  
fi  
done  
2、定时清空文件内容，定时记录文件大小

\#!/bin/bash  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
每小时执行一次脚本（任务计划），当时间为点或12点时，将目标目录下的所有文件内\#容清空，但不删除文件，其他时间则只统计各个文件的大小，一个文件一行，输出到以时\#间和日期命名的文件中，需要考虑目标目录下二级、三级等子目录的文件  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
logfile=/tmp/`date +%H-%F`.log  
n=`date +%H`  
if \[ $n -eq 00 \] || \[ $n -eq 12 \]  
then  
\#通过for循环，以find命令作为遍历条件，将目标目录下的所有文件进行遍历并做相应操作  
for i in `find /data/log/ -type f`  
do  
true > $i  
done  
else  
for i in `find /data/log/ -type f`  
do  
du -sh $i >> $logfile  
done  
fi  
3、检测网卡流量，并按规定格式记录在日志中  
\#!/bin/bash  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
\#检测网卡流量，并按规定格式记录在日志中\#规定一分钟记录一次  
\#日志格式如下所示:  
\#2019-08-12 20:40  
\#ens33 input: 1234bps  
\#ens33 output: 1235bps  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#3  
while :  
do  
\#设置语言为英文，保障输出结果是英文，否则会出现bug  
LANG=en  
logfile=/tmp/`date +%d`.log  
\#将下面执行的命令结果输出重定向到logfile日志中  
exec >> $logfile  
date +"%F %H:%M"  
\#sar命令统计的流量单位为kb/s，日志格式为bps，因此要*1000*8  
sar -n DEV 1 59|grep Average|grep ens33|awk ‘\{print $2,"\\t",“input:”,"\\t",$5*1000*8,“bps”,"\\n",$2,"\\t",“output:”,"\\t",$6*1000*8,“bps”\}’  
echo “\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#”  
\#因为执行sar命令需要59秒，因此不需要sleep  
done  
4、计算文档每行出现的数字个数，并计算整个文档的数字总数

\#!/bin/bash  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
\#计算文档每行出现的数字个数，并计算整个文档的数字总数  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
\#使用awk只输出文档行数（截取第一段）  
n=`wc -l a.txt|awk '{print $1}'`  
sum=  
\#文档中每一行可能存在空格，因此不能直接用文档内容进行遍历  
for i in `seq 1 $n`do  
\#输出的行用变量表示时，需要用双引号  
line=`sed -n "$i"p a.txt`\#wc -L选项，统计最长行的长度  
n\_n=`echo $line|sed s'/[^0-9]//'g|wc -L`  
echo  n n s u m = n\_nsum= nnsum=\[ s u m + sum+ sum\+n\_n\]  
done  
echo “sum:$sum”  
杀死所有脚本  
\#!/bin/bash  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
\#有一些脚本加入到了cron之中，存在脚本尚未运行完毕又有新任务需要执行的情况，  
\#导致系统负载升高，因此可通过编写脚本，筛选出影响负载的进程一次性全部杀死。  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
ps aux|grep 指定进程名|grep -v grep|awk ‘\{print $2\}’|xargs kill -9  
5、从 FTP 服务器下载文件  
\#!/bin/bash  
if \[ $\# -ne 1 \]; then  
echo “Usage:  0 f i l e n a m e " f i d i r = 0 filename" fi dir= 0filename"fidir=(dirname  1 ) f i l e = 1) file= 1)file=(basename $1)  
ftp -n -v << EOF \# -n 自动登录  
open 192.168.1.10 \# ftp服务器  
user admin password  
binary \# 设置ftp传输模式为二进制，避免MD5值不同或.tar.gz压缩包格式错误  
cd  d i r g e t " dir get " dirget"file”  
EOF  
6、连续输入5个100以内的数字，统计和、最小和最大  
\#!/bin/bash  
COUNT=1  
SUM=0  
MIN=0  
MAX=100  
while \[ $COUNT -le 5 \]; do  
read -p “请输入1-10个整数：” INT  
if \[\[ !  I N T =   \[ 0 − 9 \] + INT =~ ^\[0-9\]+ INT= \[0−9\]\+ \]\]; then  
echo “输入必须是整数！”  
exit 1  
elif \[\[  I N T − g t 100 \] \] ; t h e n e c h o " 输 入 必 须 是 100 以 内 ！ " e x i t 1 f i S U M = INT -gt 100 \]\]; then echo "输入必须是100以内！" exit 1 fi SUM= INT−gt100\]\];thenecho"输入必须是100以内！"exit1fiSUM=(( S U M + SUM+ SUM\+INT))  
\[ $MIN -lt KaTeX parse error: Expected 'EOF', got '&' at position 7: INT \] &̲& MIN=INT  
\[ $MAX -gt KaTeX parse error: Expected 'EOF', got '&' at position 7: INT \] &̲& MAX=INT  
let COUNT++  
done  
echo “SUM: $SUM”  
echo “MIN: $MIN”  
echo "MAX: $MAX  
用户猜数字

\#!/bin/bash \# 脚本生成一个 100 以内的随机数,提示用户猜数字,根据用户的输入,提示用户猜对了,\# 猜小了或猜大了,直至用户猜对脚本结束。\# RANDOM 为系统自带的系统变量,值为 ‐32767的随机数\# 使用取余算法将随机数变为 1‐100 的随机数num= \[ R A N D O M \[RANDOM%100+1\]echo " \[RANDOMnum" \# 使用 read 提示用户猜数字\# 使用 if 判断用户猜数字的大小关系:‐eq(等于),‐ne(不等于),‐gt(大于),‐ge(大于等于),\# ‐lt(小于),‐le(小于等于)while :do read -p "计算机生成了一个 1‐100 的随机数,你猜: " cai if \[ $cai -eq $num \] then echo “恭喜,猜对了” exit elif \[ $cai -gt $num \] then echo “Oops,猜大了” else echo “Oops,猜小了” fidone  
7、监测 Nginx 访问日志 502 情况，并做相应动作  
假设服务器环境为 lnmp，近期访问经常出现 502 现象，且 502 错误在重启 php-fpm 服务后消失，因此需要编写监控脚本，一旦出现 502，则自动重启 php-fpm 服务。

\#场景：  
\#1.访问日志文件的路径：/data/log/access.log  
\#2.脚本死循环，每10秒检测一次，10秒的日志条数为300条，出现502的比例不低于10%（30条）则需要重启php-fpm服务  
\#3.重启命令为：/etc/init.d/php-fpm restart  
\#!/bin/bash  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
\#监测Nginx访问日志502情况，并做相应动作  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
log=/data/log/access.log  
N=30 \#设定阈值  
while :do  
\#查看访问日志的最新300条，并统计502的次数  
err=`tail -n 300 $log |grep -c '502" '`  
if \[ $err -ge $N \]  
then  
/etc/init.d/php-fpm restart 2> /dev/null  
\#设定60s延迟防止脚本bug导致无限重启php-fpm服务  
sleep 60  
fi  
sleep 10  
done  
8、将结果分别赋值给变量

应用场景：希望将执行结果或者位置参数赋值给变量，以便后续使用。  
方法1：  
for i in  ( e c h o " 456 " ) ; d o e v a l a (echo "4 5 6"); do eval a (echo"456");doevalai=$idone  
echo $a4 $a5 $a6  
方法2：将位置参数192.168.1.1\{1,2\}拆分为到每个变量

num=0  
for i in $(eval echo KaTeX parse error: Expected 'EOF', got '\#' at position 9: \*);do \#̲eval将\{1,2\}分解为1 …\{num\}="$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  a r r \[ 0 \] ) I N D E X 2 = \{arr\[0\]\}) INDEX2= arr\[0\])INDEX2=(echo  a r r \[ 1 \] ) I N D E X 3 = \{arr\[1\]\}) INDEX3= arr\[1\])INDEX3=(echo $\{arr\[2\]\})

9、批量修改文件名

示例：

# touch article\_\{1…3\}.html #

# lsarticle\_1.html article\_2.html article\_3.html #

目的：把article改为bbs

方法1：

for file in $(ls *html); do  
mv KaTeX parse error: Expected group after '\_' at position 9: file bbs\_̲\{file\#**\}  
\# mv $file $(echo $file |sed -r 's/.\*(*.\*)/bbs\\1/’)  
\# mv $file $(echo KaTeX parse error: Expected group after '\_' at position 15: file |echo bbs\_̲(cut -d\_ -f2)  
done  
方法2：

for file in $(find . -maxdepth 1 -name "*html"); do  
mv KaTeX parse error: Expected group after '\_' at position 9: file bbs\_̲\{file\#*\_\}done  
方法3：

# rename article bbs \*.html #

把一个文档前五行中包含字母的行删掉，同时删除6到10行包含的所有字母  
1）准备测试文件，文件名为2.txt

第1行1234567不包含字母  
第2行56789BBBBBB  
第3行67890CCCCCCCC  
第4行78asdfDDDDDDDDD  
第5行123456EEEEEEEE  
第6行1234567ASDF  
第7行56789ASDF  
第8行67890ASDF  
第9行78asdfADSF  
第10行123456AAAA  
第11行67890ASDF  
第12行78asdfADSF  
第13行123456AAAA  
2）脚本如下：

\#!/bin/bash  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
把一个文档前五行中包含字母的行删掉，同时删除6到10行包含的所有字母  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
sed -n '1,5’p 2.txt |sed '/\[a-zA-Z\]/'d  
sed -n ‘6,10’p 2.txt |sed s’/\[a-zA-Z\]//'g  
sed -n '11,$'p 2.txt  
\#最终结果只是在屏幕上打印结果，如果想直接更改文件，可将输出结果写入临时文件中，再替换2.txt或者使用-i选项  
10、统计当前目录中以.html结尾的文件总大  
方法1：

# find . -name “\*.html” -exec du -k \{\} ; |awk ‘\{sum+=$1\}END\{print sum\}’ #

方法2：

for size in $(ls -l \*.html |awk '\{print KaTeX parse error: Expected 'EOF', got '\}' at position 2: 5\}̲'); do sum=(( s u m + sum+ sum\+size))  
done  
echo $sum  
11、扫描主机端口状态

\#!/bin/bash  
HOST=$1  
PORT=“22 25 80 8080”  
for PORT in KaTeX parse error: Expected 'EOF', got '&' at position 22: …do if echo &̲>/dev/null > /d…HOST/ P O R T ; t h e n e c h o " PORT; then echo " PORT;thenecho"PORT open"  
else  
echo “$PORT close”  
fi  
done  
用 shell 打印示例语句中字母数小于6的单词

\#示例语句：  
\#Bash also interprets a number of multi-character options.  
\#!/bin/bash  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
\#shell打印示例语句中字母数小于6的单词  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
for s in Bash also interprets a number of multi-character options.  
do  
n=`echo $s|wc -c`  
if \[ $n -lt 6 \]  
then  
echo $s  
fi  
done  
12、输入数字运行相应命令

\#!/bin/bash  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
\#输入数字运行相应命令  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
echo "*cmd menu* 1-date 2-ls 3-who 4-pwd 0-exit "  
while :  
do  
\#捕获用户键入值  
read -p “please input number :” n  
n1=`echo $n|sed s'/[0-9]//'g`  
\#空输入检测  
if \[ -z “KaTeX parse error: Expected 'EOF', got '\#' at position 26: … continue fi \#̲非数字输入检测 if \[ …n1” \]  
then  
exit  
fi  
break  
done  
case $n in  
1)  
date  
;;  
2)  
ls  
;;  
3)  
who  
;;  
4)  
pwd  
;;  
0)  
break  
;;  
\#输入数字非1-4的提示  
\*)  
echo “please input number is \[1-4\]”  
esac  
13、Expect 实现 SSH 免交互执行命令

Expect是一个自动交互式应用程序的工具，如telnet，ftp，passwd等。

需先安装expect软件包。

方法1：EOF标准输出作为expect标准输入

\#!/bin/bash  
USER=root  
PASS=123.com  
IP=192.168.1.120  
expect << EOFset timeout 30spawn ssh  U S E R @ USER@ USER@IP expect \{ “(yes/no)” \{send “yes\\r”; exp\_continue\} “password:” \{send “KaTeX parse error: Can't use function '\\r' in math mode at position 5: PASS\\̲r̲"\} \} expect "USER@*" \{send "KaTeX parse error: Can't use function '\\r' in math mode at position 2: 1\\̲r̲"\} 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  U S E R @ USER@ USER@IP  
expect \{  
“(yes/no)” \{send “yes\\r”; exp\_continue\}  
“password:” \{send “KaTeX parse error: Can't use function '\\r' in math mode at position 5: PASS\\̲r̲\\"; exp\_continu…USER@\*” \{send “df -h\\r exit\\r”; exp\_continue\}  
\}"  
方法3：将expect脚本独立出来

登录脚本：

# cat login.exp #

\#!/usr/bin/expect  
set ip \[lindex $argv \]  
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  u s e r @ user@ user@ip  
expect \{  
“(yes/no)” \{send “yes\\r”; exp\_continue\}  
“password:” \{send “KaTeX parse error: Can't use function '\\r' in math mode at position 7: passwd\\̲r̲"\} \} expect "user@*" \{send "KaTeX parse error: Can't use function '\\r' in math mode at position 4: cmd\\̲r̲"\} expect "user@*” \{send “exit\\r”\}  
expect eof  
执行命令脚本：写个循环可以批量操作多台服务器

\#!/bin/bash  
HOST\_INFO=user\_info.txt  
for ip in $(awk ‘\{print $1\}’  H O S T I N F O ) d o u s e r = HOST\_INFO) do user= HOSTINFO)douser=(awk -v I="$ip" ‘I==$1\{print $2\}’  H O S T I N F O ) p a s s = HOST\_INFO) pass= HOSTINFO)pass=(awk -v I="$ip" ‘I==$1\{print $3\}’ $HOST\_INFO)  
expect login.exp $ip $user $pass $1  
done  
Linux主机SSH连接信息：

# cat user\_info.txt #

192.168.1.120 root 123456  
创建10个用户，并分别设置密码，密码要求10位且包含大小写字母以及数字，最后需要把每个用户的密码存在指定文件中

\#!/bin/bash  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
\#创建10个用户，并分别设置密码，密码要求10位且包含大小写字母以及数字  
\#最后需要把每个用户的密码存在指定文件中\#前提条件：安装mkpasswd命令  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
\#生成10个用户的序列（00-09）  
for u in `seq -w 0 09`do  
\#创建用户  
useradd user\_$u  
\#生成密码  
p=`mkpasswd -s 0 -l 10`  
\#从标准输入中读取密码进行修改（不安全）  
echo KaTeX parse error: Expected group after '\_' at position 22: …wd --stdin user\_̲u  
\#常规修改密码  
echo -e “KaTeX parse error: Undefined control sequence: \\n at position 2: p\\̲n̲p”|passwd user\_KaTeX parse error: Expected 'EOF', got '\#' at position 4: u \#̲将创建的用户及对应的密码记录到…u $p" >> /tmp/userpassworddone  
14、监控 httpd 的进程数，根据监控情况做相应处理

\#!/bin/bash  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
\#需求：  
\#1.每隔10s监控httpd的进程数，若进程数大于等于500，则自动重启Apache服务，并检测服务是否重启成功  
\#2.若未成功则需要再次启动，若重启5次依旧没有成功，则向管理员发送告警邮件，并退出检测  
\#3.如果启动成功，则等待1分钟后再次检测httpd进程数，若进程数正常，则恢复正常检测（10s一次），否则放弃重启并向管理员发送告警邮件，并退出检测  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
\#计数器函数  
check\_service()  
\{  
j=  
for i in `seq 1 5`  
do  
\#重启Apache的命令  
/usr/local/apache2/bin/apachectl restart 2> /var/log/httpderr.log  
\#判断服务是否重启成功  
if \[  ? − e q \] t h e n b r e a k e l s e j = ? -eq \] then break else j= ?−eq\]thenbreakelsej=\[$j+1\] fi  
\#判断服务是否已尝试重启5次  
if \[ $j -eq 5 \] then  
mail.py exit  
fi  
done \}while :do  
n=`pgrep -l httpd|wc -l`  
\#判断httpd服务进程数是否超过500  
if \[ $n -gt 500 \] then  
/usr/local/apache2/bin/apachectl restart  
if \[ $? -ne \]  
then  
check\_service  
else  
sleep 60  
n2=`pgrep -l httpd|wc -l`  
\#判断重启后是否依旧超过500  
if \[ $n2 -gt 500 \]  
then  
mail.py exit  
fi  
fi  
fi  
\#每隔10s检测一次  
sleep 10done  
15、批量修改服务器用户密码

Linux主机SSH连接信息：旧密码

# cat old\_pass.txt #

192.168.18.217 root 123456 22  
192.168.18.218 root 123456 22  
内容格式：IP User Password Port

SSH远程修改密码脚本：新密码随机生成  
https://www.linuxprobe.com/books  
\#!/bin/bash  
OLD\_INFO=old\_pass.txt  
NEW\_INFO=new\_pass.txt  
for IP in $(awk ‘/\[\#\]/\{print $1\}’  O L D I N F O ) ; d o U S E R = OLD\_INFO); do USER= OLDINFO);doUSER=(awk -v I=$IP ‘I==$1\{print $2\}’  O L D I N F O ) P A S S = OLD\_INFO) PASS= OLDINFO)PASS=(awk -v I=$IP ‘I==$1\{print $3\}’  O L D I N F O ) P O R T = OLD\_INFO) PORT= OLDINFO)PORT=(awk -v I=$IP ‘I==$1\{print $4\}’  O L D I N F O ) N E W P A S S = OLD\_INFO) NEW\_PASS= OLDINFO)NEWPASS=(mkpasswd -l 8) \# 随机密码  
echo “$IP $USER $NEW\_PASS $PORT” >>  N E W I N F O e x p e c t − c " s p a w n s s h − p NEW\_INFO expect -c " spawn ssh -p NEWINFOexpect−c"spawnssh−pPORT  U S E R @ USER@ USER@IP  
set timeout 2  
expect \{  
“(yes/no)” \{send “yes\\r”;exp\_continue\}  
“password:” \{send “KaTeX parse error: Can't use function '\\r' in math mode at position 5: PASS\\̲r̲\\";exp\_continue…USER@\*” \{send “echo ‘$NEW\_PASS’ |passwd --stdin $USER\\r exit\\r”;exp\_continue\}  
\}"  
done  
生成新密码文件：

# cat new\_pass.txt #

192.168.18.217 root n8wX3mU% 22  
192.168.18.218 root c87;ZnnL 22  
16、iptables 自动屏蔽访问网站频繁的IP

场景：恶意访问,安全防范

1）屏蔽每分钟访问超过200的IP

方法1：根据访问日志（Nginx为例）  
\#!/bin/bash  
DATE= ( d a t e + A B N O R M A L I P = (date +%d/%b/%Y:%H:%M) ABNORMAL\_IP= (date\+ABNORMALIP=(tail -n500 access.log |grep $DATE |awk ‘\{a\[$1\]++\}END\{for(i in a)if(a\[i\]>100)print i\}’)  
\#先tail防止文件过大，读取慢，数字可调整每分钟最大的访问量。awk不能直接过滤日志，因为包含特殊字符。  
for IP in $ABNORMAL\_IP; do  
if \[  ( i p t a b l e s − v n L ∣ g r e p − c " (iptables -vnL |grep -c " (iptables−vnL∣grep−c"IP") -eq \]; then  
iptables -I INPUT -s $IP -j DROP fidone  
方法2：通过TCP建立的连接

\#!/bin/bash  
ABNORMAL\_IP=$(netstat -an |awk ‘ 4   / : 80 4~/:80 4 /:80/ && $6~/ESTABLISHED/\{gsub(/:\[0-9\]+/,"",$5);\{a\[$5\]++\}\}END\{for(i in a)if(a\[i\]>100)print i\}’)  
\#gsub是将第五列（客户端IP）的冒号和端口去掉  
for IP in $ABNORMAL\_IP; do  
if \[  ( i p t a b l e s − v n L ∣ g r e p − c " (iptables -vnL |grep -c " (iptables−vnL∣grep−c"IP") -eq \]; then  
iptables -I INPUT -s $IP -j DROP  
fi  
done

2）屏蔽每分钟SSH尝试登录超过10次的IP

方法1：通过lastb获取登录状态:

\#!/bin/bash  
DATE= ( d a t e + " A B N O R M A L I P = (date +"%a %b %e %H:%M") \#星期月天时分 %e单数字时显示7，而%d显示07 ABNORMAL\_IP= (date\+"ABNORMALIP=(lastb |grep “$DATE” |awk ‘\{a\[$3\]++\}END\{for(i in a)if(a\[i\]>10)print i\}’)for IP in $ABNORMAL\_IP; do  
if \[  ( i p t a b l e s − v n L ∣ g r e p − c " (iptables -vnL |grep -c " (iptables−vnL∣grep−c"IP") -eq \]; then  
iptables -I INPUT -s $IP -j DROP fidone  
方法2：通过日志获取登录状态

\#!/bin/bash  
DATE= ( d a t e + " A B N O R M A L I P = " (date +"%b %d %H") ABNORMAL\_IP=" (date\+"ABNORMALIP="(tail -n10000 /var/log/auth.log |grep “KaTeX parse error: Expected '\}', got 'EOF' at end of input: …wk '/Failed/\{a\[(NF-3)\]++\}END\{for(i in a)if(a\[i\]>5)print i\}’)”  
for IP in $ABNORMAL\_IP; do  
if \[  ( i p t a b l e s − v n L ∣ g r e p − c " (iptables -vnL |grep -c " (iptables−vnL∣grep−c"IP") -eq \]; then  
iptables -A INPUT -s  I P − j D R O P e c h o " IP -j DROP echo " IP−jDROPecho"(date +"%F %T") - iptables -A INPUT -s KaTeX parse error: Expected 'EOF', got '\#' at position 96: …半小时后恢复正常，则解除封禁 \#̲!/bin/bash \#\#\#\#…d1:’ $logfile|awk ‘\{print $1\}’|sort -n|uniq -c|sort -n > $ips  
\#利用for循环将次数超过100的IP依次遍历出来并予以封禁  
for i in `awk '$1>100 {print $2}' $ips`  
do  
$ipt -I INPUT -p tcp --dport 80 -s $i -j REJECT  
echo "`date +%F-%T` KaTeX parse error: Expected 'EOF', got '\}' at position 29: …dip.log done \}̲ unblock() \{ \#…ipt -nvL INPUT --line-numbers |grep ‘0.0.0.0/0’|awk ‘$2<10 \{print $1\}’|sort -nr\`  
do  
$ipt -D INPUT $a  
done  
$ipt -Z  
\}  
\#当时间在00分以及30分时执行解封函数  
if \[ $d2 -eq “00” \] || \[ $d2 -eq “30” \]  
then  
\#要先解再封，因为刚刚封禁时产生的pkts数量很少  
unblock  
block  
else  
block  
fi  
18、判断用户输入的是否为IP地址  
方法1:

\#!/bin/bash  
function check\_ip()\{  
IP= 1 V A L I D C H E C K = 1 VALID\_CHECK= 1VALIDCHECK=(echo $IP|awk -F. ‘$1< =255&&$2<=255&&$3<=255&&$4<=255\{print “yes”\}’)  
if echo KaTeX parse error: Can't use function '\\.' in math mode at position 24: …-E "^\[0-9\]\{1,3\}\\̲.̲\[0-9\]\{1,3\}\\.\[0-…“>/dev/null; then  
if \[  V A L I D C H E C K = = " y e s " \] ; t h e n e c h o " VALID\_CHECK == "yes" \]; then echo " VALIDCHECK=="yes"\];thenecho"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 \[\[ KaTeX parse error: Can't use function '\\.' in math mode at position 18: … =~ ^\[0-9\]\{1,3\}\\̲.̲\[0-9\]\{1,3\}\\.\[0-… \]\]; then  
FIELD1=$(echo  I P ∣ c u t − d . − f 1 ) F I E L D 2 = IP|cut -d. -f1) FIELD2= IP∣cut−d.−f1)FIELD2=(echo  I P ∣ c u t − d . − f 2 ) F I E L D 3 = IP|cut -d. -f2) FIELD3= IP∣cut−d.−f2)FIELD3=(echo  I P ∣ c u t − d . − f 3 ) F I E L D 4 = IP|cut -d. -f3) FIELD4= IP∣cut−d.−f3)FIELD4=(echo $IP|cut -d. -f4)  
if \[ $FIELD1 -le 255 -a $FIELD2 -le 255 -a $FIELD3 -le 255 -a  F I E L D 4 − l e 255 \] ; t h e n e c h o " FIELD4 -le 255 \]; then echo " FIELD4−le255\];thenecho"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：

加个死循环，如果IP可用就退出，不可用提示继续输入，并使用awk判断。

\#!/bin/bash  
function check\_ip()\{  
local IP= 1 V A L I D C H E C K = 1 VALID\_CHECK= 1VALIDCHECK=(echo $IP|awk -F. ‘$1< =255&&$2<=255&&$3<=255&&$4<=255\{print “yes”\}’)  
if echo KaTeX parse error: Can't use function '\\.' in math mode at position 24: …-E "^\[0-9\]\{1,3\}\\̲.̲\[0-9\]\{1,3\}\\.\[0-…" >/dev/null; then  
if \[  V A L I D C H E C K = = " y e s " \] ; t h e n r e t u r n e l s e e c h o " VALID\_CHECK == "yes" \]; then return else echo " VALIDCHECK=="yes"\];thenreturnelseecho"IP not available!"  
return 1  
fi  
else  
echo “Format error! Please input again.”  
return 1  
fi  
\}  
while true; do  
read -p "Please enter IP: " IP  
check\_ip $IP  
\[ $? -eq 0 \] && break || continue  
done

来源：本文转自[开源世界，点击查看原文][Link 2]。

[Link 1]: http://github.crmeb.net/u/defu
[Link 2]: http://ym.baisou.ltd/?id=475