Update CentOS6-and-CentOS7.md

Author: judasn

CentOS6-and-CentOS7.md

@@ -49,7 +49,7 @@
 ## ifconfig 没有了
 
 - 查看网络配置：`ip a`
-- 装回 ifconfig：`yum insall -y net-tools`
+- 装回 ifconfig：`yum install -y net-tools`
 
 ## 设置时区
 
@@ -62,4 +62,4 @@
 - <http://blog.topspeedsnail.com/archives/3017>
 - <http://chenbaocheng.com/2015/07/15/Centos-7-%E5%AE%89%E8%A3%85%E9%85%8D%E7%BD%AEiptables/>
 - <http://cuidehua.blog.51cto.com/5449828/1858374>
-- <http://putty.biz/760>
+- <http://putty.biz/760>