shell脚本练习

1.模拟linnux登录shell

#/bin/bash
echo -n "login:" 
read name
echo -n "password:"
read passwd
if [ $name = "cht" -a $passwd = "abc" ];then
echo "the host and password is right!"
else echo "input is error!"
fi

2.比较两个数大小

#/bin/bash
echo "please enter two number"
read a
read b
if test $a -eq $b
then echo "NO.1 = NO.2"
elif test $a -gt $b
then echo "NO.1 > NO.2"
else echo "NO.1 < NO.2" 
fi

3.查找/root/目录下是否存在该文件

#/bin/bash
echo "enter a file name:"
read a
if test  -e /root/$a 
then echo "the file is exist!"
else echo "the file is not exist!"
fi

4.for循环的使用

#/bin/bash
clear
for num in 1 2 3 4 5 6 7 8 9 10
do
    echo "$num"
done

5.命令行输入

#/bin/bash
echo "Please enter a user:"
read a
b=$(whoami)
if test $a = $b
then echo "the user is running."
else echo "the user is not running."
fi

6.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

7.如果/export/um_lpp_source下有文件，那么将其文件系统大小改为3G

#/bin/bash
while line=`ls /export/um_lpp_source`
do
        if test $line=""
        then  echo "NULL"
             sleep 1
    else echo $line
                chfs -a size=3G /export/um_lpp_source
                 exit 0
        fi
done

8.测试IP地址

#/bin/bash
for i in  1 2 3 4 5 6 7 8 9 
do
    echo "the number of $i computer is "
    ping -c 1 192.168.0.$i
done

9.如果test.log的大小大于0，那么将/opt目录下的*.tar.gz文件

 #/bin/sh
a=2
while name="test.log"
do
        sleep 1
        b=$(ls -l $name | awk '{print $5}')
        if test $b -ge $a
        #then echo "OK"
    then `cp /opt/*.tar.gz .`
        exit 0
        fi
done

10.打印读取的内容，为下面的例子做准备

#/bin/bash
while read name
do
echo $name
done

11.从0.sh中读取内容并打印

#/bin/bash
while read line
do
    echo $line
done < 0.sh

12.读取a.c中的内容并做加1运算

#/bin/bash
test -e a.c
while read line
do
    a=$(($line+1))
done < a.c
echo $a

13.普通无参数函数

#/bin/bash
p ()
{
    echo "hello"
}
p

14.给函数传递参数

#/bin/bash
p_num ()
{
    num=$1
    echo $num
}
for n in $@
do
    p_num $n
done

15.创建文件夹

#/bin/bash
while :
do
    echo "please input file's name:"
    read a
    if test -e /root/$a
    then
         echo "the file is existing Please input new file name:"
    else
        mkdir $a
        echo "you aye sussesful!"
        break 
    fi
done

16.获取本机IP地址

#/bin/bash
ifconfig | grep "inet addr:" | awk '{ print $2 }'| sed 's/addr://g'

17.查找最大文件

#/bin/bash
a=0
for  name in *.*
do
     b=$(ls -l $name | awk '{print $5}')
    if test $b -ge $a
    then a=$b
         namemax=$name
     fi
done
echo "the max file is $namemax"

18.查找当前网段内IP用户，重定向到ip.txt文件中

#/bin/bash
a=1
while :
do
    a=$(($a+1))
    if test $a -gt 255
    then break
    else
        echo $(ping -c 1 192.168.0.$a | grep "ttl" | awk '{print $4}'| sed 's/://g')
        ip=$(ping -c 1 192.168.0.$a | grep "ttl" | awk '{print $4}'| sed 's/://g')
        echo $ip >> ip.txt
    fi
done

19.打印当前用户

#/bin/bash
echo "Current User is :"
echo $(ps | grep "$$" | awk '{print $2}')

20.case语句练习

#!/bin/bash
clear
echo "enter a number from 1 to 5:"
read num
case $num in
    1) echo "you enter 1"
    ;;
    2) echo "you enter 2"
    ;;
    3) echo "you enter 3"
    ;;
    4) echo "you enter 4"
    ;;
    5) echo "you enter 5"
    ;;
    *) echo "error"
    ;;
esac

21.yes/no返回不同的结构

#!/bin/bash
clear
echo "enter [y/n]:"
read a
case $a in
    y|Y|Yes|YES) echo "you enter $a"
    ;;
    n|N|NO|no) echo "you enter $a"
    ;;
    *) echo "error"
    ;;
esac

22.杀进程

#/bin/bash
pid=`ps -ef | grep '进程相关内容' | grep -v 'grep' | awk '{ print $2}'`
if [ -n "$pid" ]; then
        kill -9 $pid
fi

23.内置命令的使用

#/bin/bash

    clear
        echo "Hello, $USER"
        echo

        echo "Today 's date id `date`"

        echo

        echo "the user is :"
        who
        echo

        echo "this is `uname -s`"
        echo

        echo "that's all folks! "

24.打印无密码用户

#/bin/bash
echo "No Password User are :"
echo $(cat /etc/shadow | grep "!!" | awk 'BEGIN { FS=":" }{print $1}')

27.

#/bin/bash

    clear
        echo "Hello, $USER"
        echo

        echo "Today 's date id `date`"

        echo

        echo "the user is :"
        who
        echo

        echo "this is `uname -s`"
        echo

        echo "that's all folks! "

28.检查端口号是否已启动

#!/bin/bash
n=1
echo "检查xxx服务..."
while true
do
        if test $n -gt 20
        then 
                echo "xxx服务启动失败"
                break
        fi

        sleep 5
        n=$(($n+1))
        port=`netstat -antp | grep "0.0.0.0:8080"`
        if [ ${#port} -gt 3 ]; then
                echo "xxx服务已经启动"
                break;
        fi
done

练习一：写一个脚本
       1.设定变量FILE的值为/etc/passwd
       2.依次向/etc/passwd中的每个用户问好，并且说出对方的ID是什么
        形如：（提示：LINE=`wc -l /etc/passwd | cut -d" " -f1`)
         Hello,root，your UID is 0.
       3.统计一个有多少个用户
     答案一：#!/bin/bash
           file="/etc/passwd"
           LINES=`wc -l $file | cut -d" " -f1`
           for I in `seq 1 $LINES`;do
           userid=`head -$I $file | tail -1 |cut -d: -f3`
           username=`head -$I $file | tail -1 |cut -d: -f1`
           echo "hello $username,your UID is $userid"
           done
           echo "there are $LINES users"
     答案二：#!/bin/bash
           file=/etc/passwd
           let num=0
           for I in `cat $file`;do
           username=`echo "$I" | cut -d: -f1`
           userid=`echo "$I" | cut -d: -f3`
           echo "Hello,$username,your UID is $userid"
           num=$[$num+1]
           done
           echo "there are $num users"
练习二：写一个脚本
      1.切换工作目录至/var
      2.依次向/var目录中的每个文件或子目录问好，形如：
        （提示：for FILE in /var/*;或for FILE in `ls /var`;)
        Hello,log
      3.统计/var目录下共有多个文件，并显示出来
  答案：#!/bin/bash
         cd /var
         let num=0
         for I in `ls /var/*`;do
         echo "hello $I"
         num=$[$num+1]
         done
         echo "the number of files is $num"
练习三：写一个脚本
      1.设定变量file的值为/etc/passwd
      2.使用循环读取文件/etc/passwd的第2,4,6,10,13,15行，并显示其内容
      3.把这些行保存至/tmp/mypasswd文件中
  答案：#!/bin/bash
       file="/etc/passwd"
       for I in 2 4 6 10 13 15;do
       exec 3>/tmp/mypasswd
       line=`head -$I $file | tail -1`
       echo "$line"
       echo "$line" >&3
       exec 3>&-
       done

练习四：写一个脚本

       传递两个整数给脚本，让脚本分别计算并显示这两个整数的和，差，积，商
        答案如下：vim test.sh
                   #!/bin/bash
                    echo "first number $1"  （表示输出第一个数）

                    echo "second number $2" （表示输出第二个数）
                    echo " $(($1+$2))"      （输出两数之和）
                    echo "$[$1-$2]"         （输出两数之差）
                    echo "$[$1*$2]"         （输出两数之积）

                    echo "$[$1/$2]"         （输出两数之商）
                    :wq                    （表示保存并退出vi编辑器）
                    chmod +x test.sh       （给test.sh执行的权限）
                    ./test.sh 2 3          （传递两个参数并执行脚本     

作业一：写一个脚本：

       1.创建目录/tmp/scripts

       2.切换工作目录至此目录中

       3.复制/etc/pam.d目录至当前目录，并重命名为test

       4.将当前目录的test及其里面的文件和子目录的属主改为redhat

       5.将test及其子目录中的文件的其它用户的权限改为没有任何权限

   答案：
       #!/bin/bash
       mkdir -v /tmp/scripts
       cd /tmp/scripts
       cp -r /etc/pam.d ./test
       chown -R redhat ./test
       chmod -R o=--- ./test

作业二：写一个脚本

       1.显示当前系统日期和时间，而后创建目录/tmp/lstest

       2.切换工作目录至/tmp/lstest

       3.创建目录a1d，b56e，6test

       4.创建空文件xy，x2y，732

       5.列出当前目录下以a，x或者6开头的文件或目录

       6.列出当前目录下以字母开头，后跟一个任意数字，而后跟任意长度字符的文件或目录

   答案：
       #!/bin/bash
       date
       mkdir -pv /tmp/lstest
       cd /tmp/lstest
       mkdir a1d b56e 6test
       touch xy x2y 732
       ls [ax6]*
       ls [[:alpha:]][[:digit:]]*

            
作业三：写一个脚本
        添加10个用户user1到user10，但要求只有用户不存在的情况下才能添加
  答案：
       #!/bin/bash
       for I in `seq 1 10`;do
       cut -d: -f1 /etc/passwd |grep "user$I" 2>>/tmp/etc.err || useradd user$I
       done
作业四：写一个脚本
       通过ping命令测试192.168.0.151到192.168.0.254之间的所有主机是否在线
       如果在线，就显示“ip is up”
       如果不在线，就显示“ip is down”
      答案： #!/bin/bash
       for I in `seq 151 254`;do
       ping -c1 -w1 192.168.0.$I &>/dev/null && echo "192.168.0.$I is up" ||        echo "192.168.0.$I is down"
       done

 

1、实现批量添加20个用户，用户名为user1-20，密码为user+123

#!/bin/bash

count=$1

if [ -n "$count" ]
then 
    for ((i=1;i<=$count;i++))
    do
    useradd -d /home/user_$i -s /bin/bash user_$i;
    echo user_"$i"123 |passwd --stdin user_$i;
   done
else
    echo "$count is empty"
fi

2、100个数相加，最大值，最小值

#!/bin/bash
sum=0
for i in `seq 0 1 99`
do
    echo "第"$i"次"
    read -p "请输入数字" n
    a=$n
    sum=$[$sum+$n]
done
echo "最大值"
echo ${a}|sed 's//
/g'|sort -r|sed -n '1'p
echo "最小值"
echo ${a}|sed 's//
/g'|sort -n|sed -n '1'p
echo $sum
~