CentOS使用yum方式安装指定版本的PHP

1.查看是否已安装PHP及PHP的版本。如果已经安装老版本PHP，则删除。
通过yum list installed | grep php可以查看所有已安装的php软件
使用yum remove php　进行删除
2.添加yum源，推荐webtatic、rpmforge、163。
CentOs 5.x 
rpm -Uvh http://mirror.webtatic.com/yum/el5/latest.rpm 
CentOs 6.x 
rpm -Uvh http://mirror.webtatic.com/yum/el6/latest.rpm 
CentOs 7.X 
rpm -Uvh https://mirror.webtatic.com/yum/el7/epel-release.rpm 
rpm -Uvh https://mirror.webtatic.com/yum/el7/webtatic-release.rpm
//rpmforge
#32位：  
wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.1-1.el5.rf.i386.rpm  
rpm -ivh rpmforge-release-0.5.1-1.el5.rf.i386.rpm  
#64位：  
wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.1-1.el5.rf.x86_64.rpm  
rpm -ivh rpmforge-release-0.5.1-1.el5.rf.x86_64.rpm  
3.查看已经安装的源。
yum repolist
或者
ls /etc/yum.repos.d/ 
4.安装php。
yum install php55w
yum install php54w
yum install php56w
yum install php70w

5.查看php版本
php -v
PHP 5.4.33 (cli) (built: Sep 19 2014 19:58:27)
Copyright (c) 1997-2014 The PHP Group
Zend Engine v2.4.0, Copyright (c) 1998-2014 Zend Technologies