CentOS 6.x安装gcc 4.8/4.9/5.2

1、gcc 4.8

cd /etc/yum.repos.d 
wget http://people.centos.org/tru/devtools-2/devtools-2.repo

yum install devtoolset-2-gcc 
yum install devtoolset-2-binutils 
yum install devtoolset-2-gcc-gfortran 
yum install devtoolset-2-gcc-c++
source /opt/rh/devtoolset-2/enable

2、gcc 4.9

yum install centos-release-scl-rh centos-release-scl
yum check-update
yum install devtoolset-3-gcc  devtoolset-3-gcc-c++
source /opt/rh/devtoolset-3/enable

3、gcc 5.2

yum install centos-release-scl-rh centos-release-scl
yum check-update
yum install devtoolset-4-gcc  devtoolset-4-gcc-c++
source /opt/rh/devtoolset-4/enable

ref: http://mirror.centos.org/centos/6/sclo/