1、编写脚本/root/bin/createuser.sh，实现如下功能：使用一个用户名做为参 数，如果指定参数的用户存在，就显示其存在，否则添加之；显示添加的用户 的id号等信息
#!/bin/bash
read -p "please input your username: " n
useradd $n &> /dev/null
if [ "$?" == "0" ]
then
echo "user info: `cat /etc/passwd | grep -E "\<^$n\>"`"
else
echo "user already exists"
fi
2、编写脚本/root/bin/yesorno.sh，提示用户输入yes或no,并判断用户输入的 是yes还是no,或是其它信息
#!/bin/bash read -p "please input yes or no: " n case $n in [Yy][Ee][sS]|[Yy]) echo "you input is yes" ;; [Nn][oO]|[Nn]) echo "you input is no" ;; *) echo "you input is other info" ;; esac
3、编写脚本/root/bin/filetype.sh,判断用户输入文件路径，显示其文件类型 （普通，目录，链接，其它文件类型）
#!/bin/bash
read -p "please input file path: " n
if [ -f "$n" ]
then
echo "$n is 普通文件";
elif [ -b "$n" ]
then
echo "$n is 块设备文件";
elif [ -c "$n" ]
then
echo "$n is 字符设备文件";
elif [ -h "$n" ]
then
echo "$n is 符号链接文件"
elif [ -d "$n" ]
then
echo "$n is 目录文件";
elif [ -p "$n" ]
then
echo "$n is 管道文件";
elif [ -s "$n" ]
then
echo "$n is 套接字文件";
else
echo "$n unknown"
fi
4、编写脚本/root/bin/checkint.sh,判断用户输入的参数是否为正整数
#!/bin/bash read -p "please input your charactor: " n m=`echo $n | sed -n -r 's/[0-9]//gp'` if [ ! "n$m" == "n" ] then echo "please restart input" elif [ "$n" == "0" ] then echo "your input is 0" else echo "your input is 正整数" fi
5、判断/var/目录下所有文件的类型
#!/bin/bash
for n in /var/*
do
if [ -f "$n" ]
then
echo "$n is 普通文件";
elif [ -b "$n" ]
then
echo "$n is 块设备文件";
elif [ -c "$n" ]
then
echo "$n is 字符设备文件";
elif [ -h "$n" ]
then
echo "$n is 符号链接文件"
elif [ -d "$n" ]
then
echo "$n is 目录文件";
elif [ -p "$n" ]
then
echo "$n is 管道文件";
elif [ -s "$n" ]
then
echo "$n is 套接字文件";
else
echo "$n unknown"
fi
done
6、添加10个用户user1-user10，密码为指定字符
#!/bin/bash
for n in user{1..10}
do
useradd $n
if [ "$?" = "0" ]
then
echo "12345678" | passwd --stdin $n
else
echo "用户存在"
fi
done
7、/etc/rc.d/rc3.d目录下分别有多个以K开头和以S开头的文件；分别读取每个文件， 以K开头的输出为文件加stop，以S开头的输出为文件名加start，如K34filename stop S66filename start
#!/bin/bash
for i in /etc/rc.d/rc3.d/[SK]* ;do
if [ $(basename $i | cut -c1) == "K" ] ;then
echo "`basename $i` stop"
else
echo "`basename $i` start"
fi
done
8、编写脚本，提示输入正整数n的值，计算1+2+…+n的总和
#!/bin/bash
read -p "please input num: " n
for (( i=1;i<="$n";i++ ))
do
sum=$[$sum+$i]
done
echo $sum
```
9、计算100以内所有能被3整除的整数之和
#!/bin/bash
n=0
for i in {1..100};
do
if [ $[$i%3] -eq 0 ]
then
n=$[$n+$i]
fi
done
echo "sum=$n"
10、编写脚本，提示请输入网络地址，如192.168.0.0，判断输入的网段中主机在线状态
#!/bin/bash
f=`mktemp /tmp/ping.XXXXXXX`
read -p "please input you want to test: " ip
n=`echo $ip | cut -d'.' -f1-3`
for i in {1..255}
do
{ m=$n.$i
ping -w1 -c1 $m &> /dev/null && echo "$m is up!" && echo $m >> $f
}&
done
11、打印九九乘法表
#!/bin/bash
for i in {1..9}
do
for j in $(seq 1 $i) ;do
echo -ne "${j}x${i}=$[i*j]\t"
done
echo
done
12、在/testdir目录下创建10个html文件,文件名格式为数字N（从1到10）加随机8个字 母，如：1AbCdeFgH.html
#!/bin/bash
for i in {1..10}
do
n=`openssl rand -base64 64 | tr -dc '[a-zA-Z]' | head -c8`
touch /testdir/$i$n.html
done
13、打印等腰三角形
#!/bin/bash
until read -p "place input number " line ;do
if [[ "$line" =~ [0-9]+ ]] ;then
continue
fi
done
for i in `seq 1 $line` ;do
space=$[line-i]
star=$[2*i-1]
for j in `seq 1 $space` ; do
echo -e " \c"
done
for k in `seq 1 $star`; do
clocr=$[RANDOM%7+31]
echo -e "\e[1;${clocr}m*\e[0m\c"
done
echo
done
14、编写脚本，求100以内所有正奇数之和
#!/bin/bash
n=0
for i in {1..100};
do
if [ $[$i%2] -eq 1 ]
then
n=$[$n+$i]
fi
done
echo "sum=$n"
15、编写脚本，提示请输入网络地址，如192.168.0.0，判断输入的网段中主机 在线状态，并统计在线和离线主机各多少
#!/bin/bash
f=`mktemp /tmp/ping.XXXXXXX`
read -p "please input you want to test: " ip
n=`echo $ip | cut -d'.' -f1-3`
for i in {1..255}
do
{ m=$n.$i
ping -w1 -c1 $m &> /dev/null && { echo "$m is up!"; echo $m >> $f; }
}&
done
g=`cat "$f" | wc -l`
j=$[255-$g]
echo "up num: $g; down num: $j"
16、编写脚本，打印九九乘法表
#!/bin/bash
for i in {1..9}
do
for j in $(seq 1 $i) ;do
echo -ne "${j}x${i}=$[i*j]\t"
done
echo
done
17、编写脚本，利用变量RANDOM生成10个随机数字，输出这个10数字，并显 示其中的最大值和最小值
#!/bin/bash
let i=0,min=max=$RANDOM
echo "$min "
while [ $i -lt 9 ];do
ran=$RANDOM
echo "$ran "
if [ $ran -ge $max ];then
let max=ran
fi
if [ $ran -le $min ];then
let min=ran
fi
let i+=1
done
echo "max is: $max ,min is: $min"
18、编写脚本，实现打印国际象棋棋盘
#!/bin/bash
let x=y=1
h=8
while [ $x -le $h ];do
while [ $y -le $h ];do
if [ $[(x+y)%2] -eq 0 ] ;then
echo -en "\033[47m \033[0m"
else
echo -en "\033[40m \033[0m"
fi
let y+=1
done
echo
let x+=1,y=1
done
19、后续六个字符串：efbaf275cd、4be9c40b8b、44b2395c46、f8c8873ce0、b902c16c8b、ad865d2f63是通过对随机数变量RANDOM随机 执行命令： echo $RANDOM|md5sum|cut –c1-10 后的结果，请破解这些 字符串对应的RANDOM值
#!/bin/bash
ch=(efbaf275cd 4be9c40b8b 44b2395c46 f8c8873ce0 b902c16c8b ad865d2f63)
for num in `seq 0 65535`;do
chnum=`echo $num | md5sum | cut -c 1-10`
for n in ${ch[*]}; do
if [ "$chnum" == "$n" ];then
echo "$n --> $num"
fi
done
done
20、每隔3秒钟到系统上获取已经登录的用户的信息；如果发现用户hacker登录， 则将登录时间和主机记录于日志/var/log/login.log中,并退出脚本
#!/bin/bash username=cent { while true ;do if who | egrep "^\b$username\b" &> /dev/null ;then who | egrep "^\b$username\b" >> /var/log/login.log echo "$username 已经登录" echo "fuck ,go out my system" | write $username else echo "$username 已经下线" fi sleep 3 done }
21、随机生成10以内的数字，实现猜字游戏，提示比较大或小，相等则退出
#!bin/bash lim=10 let key=$RANDOM%lim read -p "please input a number less than $lim: " num until false;do if [ $num -le $lim &> /dev/null ] && [ $num -ge 0 &> /dev/null ] ;then if [ $num -lt $key ];then read -p "is small,please input again: " num elif [ $num -gt $key ];then read -p "is big,please input again: " num else echo "you are right,you are very clever" break fi else read -p "error,please input a number less than ten: " num fi done
22、用文件名做为参数，统计所有参数文件的总行数
#!/bin/bash
let z=0
while read -p "please input file path: " n
do
m=`cat "$n" | wc -l`
z=$[$z+$m]
echo "sum line: $z"
if (("$z" > "5000"))
then
echo "cache will be full"
break
fi
done
23、用二个以上的数字为参数，显示其中的最大值和最小值
#!/bin/bash
while read -p "please input two number: " n m
do
if (("$n" > "$m"))
then
max=$[$n]
min=$[$m]
echo "max=$max; min=$min"
elif (("$n" < "$m"))
then
max=$[$m]
min=$[$n]
echo "max=$max; min=$min"
else
echo "two num equal"
fi
done
