sudo vim /etc/yum.repos.d/CentOS-Base.repo
# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client. You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the
# remarked out baseurl= line instead.
#
#
[base]
name=CentOS-$releasever - Base
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
baseurl=http://mirrors.163.com/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
#released updates
[updates]
name=CentOS-$releasever - Updates
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
baseurl=http://mirrors.163.com/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
baseurl=http://mirrors.163.com/centos/$releasever/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
baseurl=http://mirrors.163.com/centos/$releasever/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib
baseurl=http://mirrors.163.com/centos/$releasever/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
接下来里面更新：sudo yum update
更新完后，下载几个字体，wqy-microhei.ttc，YaHeiConsolas，Microsoft_YaHei等，然后在系统设置->外观里面修改默认字体。
———RPMforge repository—————
有时候有些软件可能在中心的repo里面的没有，这时候最好使用RPMforge repository，但是这样来的话升级的时候会有version冲突，于是可以这样子设置：
先下载RPMForge的repo：
wget http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.2-1.el6.rf.x86_64.rpm
安装：
rpm -ivh rpmforge-release-0.5.2-1.el6.rf.x86_64.rpm
you’ll get a warning, but it will proceed based on the flags that you set. warning: rpmforge-release-0.5.2-1.el6.rf.x86_64.rpm : Header V3 DSA/SHA1 Signature, key ID 6b8d79e6: NOKEY
Preparing... ########################################### [100%]
1:rpmforge-release ########################################### [100%]
接下来最最重要的就是设置优先级了：
Now you need to edit /etc/yum.repos.d/CentOS-Base.repo and add these priorities to the bottoms of each of the following repo sections:
[base]
priority=1
[updates]
priority=1
[extras]
priority=1
Save your changes on this file and edit the rpmforge.repo file. You’ll only need to edit the one repository section.
[rpmforge]
priority=5
Save your changes and you’re finished.
-----------开始更新浏览器版本至firefox18-------------
参考文章：http://www.if-not-true-then-false.com/2011/install-firefox-on-fedora-centos-red-hat-rhel/
备份下先：
tar -cvzf $HOME/mozilla-firefox-profiles-backup.tar.gz $HOME/.mozilla/firefox/
su -
## Remi Dependency on CentOS 6 and Red Hat (RHEL) 6 ##
rpm -Uvh http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm
## CentOS 6 and Red Hat (RHEL) 6 ##
rpm -Uvh http://rpms.famillecollet.com/enterprise/remi-release-6.rpm
检查有用的版本：
yum --enablerepo=remi list firefox
# 更新或者安装 Mozilla Firefox 18/10
yum --enablerepo=remi update firefox
# 启动 Firefox 18/10
firefox
firefox安装那个flash插件：
去adobe的官网上去下载，选择tar.gz包，解压，得到libflashplayer.so, 把这个文件复制到 /home/username/.mozilla/plugins目录下，重启firefox就行了。要注意的是，libflashplayer.so必须属于指定普通用户。
-------------install google chrome 24------------
sudo vim /etc/yum.repos.d/CentOS-Base.repo
[google64]
name=Google – x86_64
baseurl=http://dl.google.com/linux/rpm/stable/x86_64
enabled=1
gpgcheck=1
gpgkey=https://dl-ssl.google.com/linux/linux_signing_key.pub
安装稳定版本：sudo yum install google-chrome-stable