bash每日一练，8个经典脚本示例

Posted 2021-05-02 运维部落

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bash脚本示例

一、ping C类网地址

#!/bin/bash
read -p "C NETWORK:" MYNET
PINGNET=`echo $MYNET | sed 's/\([0-9.]*\)\ .[0-9]*/\1/g'`
let I=1
while [ $I -le 254 ];do
  ping –c1 –W1 $PINGNET.$I &>/dev/null
   [ $? -eq 0 ] && echo "$PINGNET.$I  online." || echo "$PINGNET.$I offline."
let  I++
done

二、ping B类网地址

#!/bin/bash
read -p "B network:" MYNET
PINGNET=`echo $MYNET | sed 's/\([0-9]\{1,3\}\.[0-9]\{1,3\}\)\..*/\1/g'`
for P in {0..255}; do
      for I in {1..255}; do
  if ping -c1 -W2 $PINGNET.$P.$I &>/dev/null; then
    echo  "$PINGNET.$P.$I is online."
      else
        echo "$PINGNET.$P.$I is offline."
  fi
    done
done

三、删除当前目录下大小为0的文件

#!/bin/bash  
for filename in `ls`  
do  
    if test -d $filename  
    then b=0  
    else      
       a=$(ls -l $filename | awk '{ print $5 }')  
            if test $a -eq 0  
             then rm $filename  
             fi  
        fi        
done

四、实现grep -i的功能

/home/lee#cat Grep
#!/bin/bash
#
(($#!=2))||[[ ! -f $2 ]]&&{ echo "Usage:$(basename $0) <patten> filename"; exit 1; }
str=$(echo $1|od -b)
str=${str% *}
str=${str#* }
patten=$(
for i in $str;do
        [[ $i == 14[0-9] ]] && echo -ne "\\0133\\0${i/4/0}\\0$i\\0135" ||\
        echo -ne "\\0133\\0${i/0/4}\\0$i\\0135"
done
)
while read line;do
        [[ $line == *$patten* ]] && echo $line
done<$2

五、生产八位的随机密码

#!/bin/bash
MATRIX="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
LENGTH="8"
while [ "${n:=1}" -le "$LENGTH" ]
do
 PASS="$PASS${MATRIX:$(($RANDOM%${#MATRIX})):1}"
 let n+=1
done
echo "$PASS"      # ==> Or, redirect to a file, as desired.
exit 0

六、将网站访问超过阀值的IP地址加入黑名单

#! /bin/bash
# fuckgo.sh
# by platinum

MYIP="xxx.xxx.xxx.xxx"
ftp_who()
{
        netstat -an|grep $MYIP':21 '|grep -v LISTEN|grep -v ESTABLISHED|awk '{print $5;}'|awk -F':' '{print $1;}'|sort|uniq -c|awk '{print $1"="$2;}'
}

http_who()
{
        netstat -an|grep $MYIP':80 '|grep -v LISTEN|awk '{print $5;}'|awk -F':' '{print $1;}'|sort|uniq -c|awk '{print $1"="$2;}'
}

for _un in $(ftp_who)
do
        IP=`echo $_un|gawk -F'=' '{print $2}'`
        NUM=`echo $_un|awk -F'=' '{print $1}'`
        if [ $NUM -gt 5 ] && [ -z "`iptables -vnL|grep $IP`" ]
        then
                iptables -I INPUT -s $IP -p tcp --dport 21 -m state --state NEW,RELATED,ESTABLISHED -j DROP
                echo "`date` FTP $IP NUM: $NUM" >> /var/log/fuck.log
        fi
done

for _un in $(http_who|grep -v $MYIP)
do
        IP=`echo $_un|gawk -F'=' '{print $2}'`
        NUM=`echo $_un|awk -F'=' '{print $1}'`
        if [ $NUM -gt 20 ] && [ -z "`iptables -vnL|grep $IP`" ]
        then
                iptables -I INPUT -s $IP -p tcp --dport 80 -m state --state NEW,RELATED,ESTABLISHED -j DROP
                echo "`date` WEB $IP NUM: $NUM" >> /var/log/fuck.log
        fi
done

#!/bin/bash
search () {
for dir in `echo *`
do
if [ -d "$dir" ] ; then # ==> If it is a directory (-d)...
zz=0                    # ==> Temp variable, keeping track of directory level.
while [ $zz != $1 ]     # Keep track of inner nested loop.
do
echo -n "| "        # ==> Display vertical connector symbol,
zz=`expr $zz + 1`   # ==> Increment zz.
done
if [ -L "$dir" ] ; then # ==> If directory is a symbolic link...
echo "+---$dir" `ls -l $dir | sed 's/^.*'$dir' //'`
else
echo "+---$dir"       # ==> Display horizontal connector symbol...
numdirs=`expr $numdirs + 1` # ==> Increment directory count.
if cd "$dir" ; then         # ==> If can move to subdirectory...
search `expr $1 + 1`      # with recursion ;-)
cd ..
fi
fi
fi
done
}
if [ $# != 0 ] ; then
cd $1 # move to indicated directory.
fi
echo "Initial directory = `pwd`"
numdirs=0
search 0
echo "Total directories = $numdirs"
exit 0

八、打印杨辉三角

#!/bin/bash
if (test -z $1) ;then
 read -p "Input Max Int Lines:" MAX
else
        MAX=$1
fi
for ((i=1;i<=MAX;i++))
do
    for ((j=1;j<=i;j++))
    do
      f=$(($i-1))
      g=$(($j-1))
          if [ "$j" == 1 ];then
           declare SUM_${i}_$j=1
          else
           declare  A=$[SUM_${f}_$j]
           declare  B=$[SUM_${f}_$g]
           declare  SUM_${i}_$j=`expr $A + $B`
          fi
      echo -n $[SUM_${i}_$j]
      echo -en "  "
    done
echo  "  "
done