yum check-update
yum update
yum clean all
提醒下各位同学yum的remove不要随便乱玩，有时候会要命的！
http://pkgs.repoforge.org/rpmforge-release/
增加新的yum prepo
wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.1-1.el5.rf.i386.rpm
rpm -Uhv rpmforge-release-0.5.1-1.el5.rf.i386.rpm