```
sudo yum install centos-release-scl
```

```
sudo yum install devtoolset-3-toolchain
```

```
scl enable devtoolset-3 bash
```

Check to see the gcc version is updated
```
gcc --version
```
i.e.
```
jungo@dev-jo ~ $ gcc --version
gcc (GCC) 4.9.2 20150212 (Red Hat 4.9.2-6)
...
```

Now add `source /opt/rh/devtoolset-3/enable` to `~/.bashrc`