1、RHEL/CentOS/SL Linux 6.x 下安裝 EPEL6 yum源：
32位系統選擇：
rpm -ivh download.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm
64位系統選擇：
rpm -ivh download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
導入key：
rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
2、默認會在/etc/yum.repos.d/下創建epel.repo和epel-testing.repo兩個配置文件，epel.repo的內容如下：
[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
#baseurl=download.fedoraproject.org/pub/epel/6/$basearch
mirrorlist=mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$basearch
failovermethod=priority
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
[epel-debuginfo]
name=Extra Packages for Enterprise Linux 6 - $basearch - Debug
#baseurldownload.fedoraproject.org/pub/epel/6/$basearch/debug
mirrorlist=mirrors.fedoraproject.org/metalink?repo=epel-debug-6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=1
[epel-source]
name=Extra Packages for Enterprise Linux 6 - $basearch - Source
#baseurl=download.fedoraproject.org/pub/epel/6/SRPMS
mirrorlist=mirrors.fedoraproject.org/metalink?repo=epel-source-6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=1
如果想使用比較新的軟件，可以啟用[epel-testing]源，把裏面的enabled=0改成enabled=1就可以。
3、yum安裝nginx測試看看：
yum install nginx
二、啟用remi的RHEL6 yum源：
1、RHEL/CentOS/SL Linux 6.x下安裝remi的RHEL6 yum源：
rpm -ivh rpms.famillecollet.com/enterprise/remi-release-6.rpm
導入key：
rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-remi
2、默認會在/etc/yum.repos.d/下創建remi.repo配置文件，remi.repo的內容如下：
[remi]
name=Les RPM de remi pour Enterprise Linux $releasever - $basearch
#baseurl=rpms.famillecollet.com/enterprise/$releasever/remi/$basearch/
mirrorlist=rpms.famillecollet.com/enterprise/$releasever/remi/mirror
enabled=0
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-remi
failovermethod=priority
[remi-test]
name=Les RPM de remi en test pour Enterprise Linux $releasever - $basearch
#baseurl=rpms.famillecollet.com/enterprise/$releasever/test/$basearch/
mirrorlist=rpms.famillecollet.com/enterprise/$releasever/test/mirror
enabled=0
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-remi
3、yum安裝MySQL 5.5看看：
yum --enablerepo=remi install mysql mysql-server
如果是升級MySQL，請用：
yum --enablerepo=remi update mysql mysql-server