升级后查看版本为新的版本。
但是：无法正常编译。
Paste the steps:
1. Easy installation Operating environment CentOS6.5
64bit, the original version 4.4.7, cannot support the features of C++11~, hope to upgrade to 4.8.2
Cannot be upgraded by yum, you need to manually download the installation package and compile
1.1 Obtain and unzip the installation package
wget http://ftp.gnu.org/gnu/gcc/gcc-4.8.2/gcc-4.8.2.tar.bz2
tar -jxvf gcc-4.8.2.tar.bz2
Of course, http://ftp.gnu.org/gnu/gcc has all gcc versions for download, the latest version is already 4.9.2.
1.2 Download dependencies for compilation needs
Reference [1] said: This magic script file will help us download, configure, and install dependent libraries, which can save us a lot of time and effort.
cd gcc-4.8.2
./contrib/download_prerequisites
1.3 Create a directory for storing compiled files
mkdir gcc-build-4.8.2
cd gcc-build-4.8.2
1.4 Generate Makefile
../configure -enable-checking=release -enable-languages=c,c++,fortran -disable-multilib --prefix=/usr/local/gcc-4.8.2
1.5 Compile (Note: This step is very time-consuming)
make
configure: error: `LDFLAGS' has changed since the previous run:
configure: former value:
configure: current value: -static-libstdc++ -static-libgcc
configure: error: changes in the environment can compromise the build
configure: error: run `make distclean' and/or `rm ./config.cache' and start over
make[2]: *** [configure-stage1-gmp] Error 1
make[2]: Leaving directory `/home/aimin/software/gcc-4.8.2/gcc-build-4.8.2'
make[1]: *** [stage1-bubble] Error 2
make[1]: Leaving directory `/home/aimin/software/gcc-4.8.2/gcc-build-4.8.2'
make: *** [all] Error 2
sudo yum -y install glibc-devel.i686 glibc-devel
1.6, install
sudo make install
Second, verify the installation restart, and then check the gcc version:
gcc -v
tries to write a C++11 feature program block tryCpp11.cc, using shared_ptr
cp /usr/local/lib64/libstdc++.so.6.0.20 /usr/lib64
rm -rf /usr/lib64/libstdc++.so.6
ln -s /usr/lib64/libstdc++.so.6.0.20 /usr/lib64/libstdc++.so.6
strings /usr/lib64/libstdc++.so.6 | grep GLIBC
如果发现版本没有变化，
可以删除旧版本的gcc，如果旧版的是用yum安装的，可以使用 yum remove gcc。
然后把新安装的gcc的bin目录（/usr/local/gcc-4.8.2/bin）添加到环境变量（PATH）中，/etc/profile 文件中。
让/etc/profile文件修改后立即生效 ,可以使用如下命令:
source /etc/profile
gcc --version
g++ --version
gfortran --version