作业

1、在ftp://192.168.0.254/pub/gls/centes.repo下载到tmp目录

#!/bin/bash

cd /tmp

wget ftp://192.168.0.254/pub/gls/centos.repo

然后再执行bash tmp 即可

2.、判断文件是否存在，是就修改其中的baseurl=htttp://mirrors,163,com/centos.repo为http://mirros.sohu.com/centos 然后将修改后的文件移动到/etc/repos,d/然后再安装

[ -e centos.repo ] && grep "^baseurl=http://mirrors.163.com" centos.repo | sed -i "s/baseurl=http:\/\/mirrors.163.com\/centos\/*/baseurl=http:\/\/mirrors.souhu.com\/centos/g" centos.repo && mv centos.repo /etc/repos.d

&& cd /etc  yum install pidgin

3、

一百以内的偶数之和

let i=1

let sum=0

for i in {1..100};do

   if [ $[$i%2] -eq 0 ];then

   let sum+=$i

  fi

 let i++

done

echo "the sum is $sum:"

let i=2

[ i=i+2 ] && [ sum+=$i ]

let i++

echo "the sum is $sum"

4.、判断俩个数的大小

if [ $1 -ge $2 ]; then

echo "the max is :$1"

else

echo "the max is :$2"

fi

5、

ping c类网络：

#date: 2010-12-22

for i in {1..10};do

if ping -c1 -W1 192.168.0.$i &> /dev/null;then

 echo "$i is online"

 echo "$i is offline"

用函数：

~#!/bin/bash

function cping {

NET=`echo "$1" | sed "s/\([0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\).*/\1/g"`

 let i=1

ping -c1 -W1 $NET.$i &> /dev/null

[ $? -eq 0 ] && echo "the $NET.$i is online" || echo "the $NET.$i is outline"

}

read -p "Please input your ip :" MYIP

cping $MYIP