gcc升级（含命令行升级、手动升级两种方式）

1.yum源替换

默认yum源不可用，替换为国内源
替换前：

1.1 备份原始repo配置文件

cd /etc/yum.repos.d/
mkdir bak
mv CentOS-* bak/

1.2 重新配置CentOS-Base.reporepo文件

若服务器有wget命令，可复制下述命令直接从互联网拉取阿里配置源到服务器
wget https://mirrors.aliyun.com/repo/Centos-7.repo -O /etc/yum.repos.d/CentOS-Base.repo若服务器为最小化安装，没有wget命令，可以直接在/etc/yum.repos.d/目录下，创建名称为CentOS-Base.repo的文件，把下述内容复制到配置文件中

CentOS-Base.reporepo全内容

[base]
name=CentOS-$releasever - Base - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/os/$basearch/http://mirrors.aliyuncs.com/centos/$releasever/os/$basearch/http://mirrors.cloud.aliyuncs.com/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7#released updates 
[updates]
name=CentOS-$releasever - Updates - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/updates/$basearch/http://mirrors.aliyuncs.com/centos/$releasever/updates/$basearch/http://mirrors.cloud.aliyuncs.com/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/extras/$basearch/http://mirrors.aliyuncs.com/centos/$releasever/extras/$basearch/http://mirrors.cloud.aliyuncs.com/centos/$releasever/extras/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/centosplus/$basearch/http://mirrors.aliyuncs.com/centos/$releasever/centosplus/$basearch/http://mirrors.cloud.aliyuncs.com/centos/$releasever/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/contrib/$basearch/http://mirrors.aliyuncs.com/centos/$releasever/contrib/$basearch/http://mirrors.cloud.aliyuncs.com/centos/$releasever/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7

修改后：

1.3 清除缓存并重新创建

yum clean all
yum makecache

2. gcc安装

yum -y install gcc gcc-c++

安装后，默认版本为：4.8.5

3.命令行升级gcc

yum -y install centos-release-scl
yum -y install devtoolset-9-gcc devtoolset-9-gcc-c++ devtoolset-9-binutilse
scl enable devtoolset-9 bash
echo "source /opt/rh/devtoolset-9/enable">> /etc/profile

执行过程中出现异常信息：
1.安装：centos-release-scl时正常，安装：devtoolset-9-gcc、devtoolset-9-gcc-c++、devtoolset-9-binutilse时出现报错

解决方法： 查看报错信息，报错为：CentOS-SCLo-scl-rh.repo文件地址无法访问
使用阿里对应的配置文件，修改改文件内容
CentOS-SCLo-scl-rh.repo文件全内容

[centos-sclo-rh]
name=CentOS-$releasever - SCLo rh
baseurl=https://mirrors.aliyun.com/centos/$releasever/sclo/$basearch/rh/
gpgcheck=1
enabled=1
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7

CentOS-SCLo-scl.repo文件内容

[centos-sclo-sclo]
name=CentOS-$releasever - SCLo sclo
baseurl=https://mirrors.aliyun.com/centos/$releasever/sclo/$basearch/sclo/
gpgcheck=1
enabled=1
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7

2.清除缓存，重新创建缓存后，再次安装devtoolset-9-gcc、devtoolset-9-gcc-c++、devtoolset-9-binutilse出现异常信息

解决方法： 查看报错信息为密钥问题，尝试在安装时候，直接安装，不校验密钥

yum -y install devtoolset-9-gcc devtoolset-9-gcc-c++ devtoolset-9-binutilse --nogpgcheck

成功安装

在当前shell终端中使devtoolset-9生效，配置永久使用devtoolset-9，查看gcc版本，已经成功升级到9.3.1

4.手动升级

以9.3.0为例

4.1 安装包下载

# 创建存放目录
mkdir -p /apps/scripts
cd /apps/scripts/# gcc安装包下载
下载地址：https://mirrors.aliyun.com/gnu/gcc/gcc-9.3.0/gcc-9.3.0.tar.gz
可下载后上传，或直接在服务器上从互联网拉取
wget https://mirrors.aliyun.com/gnu/gcc/gcc-9.3.0/gcc-9.3.0.tar.gz

4.2 解压

tar -xzf gcc-9.3.0.tar.gz
cd gcc-9.3.0

[root@rhel76 gcc-10.1.0]# mkdir build[root@rhel76 gcc-10.1.0]# cd build/[root@rhel76 build]# …/configure --prefix=/usr/local/gcc-10.1.0/ --enable-checking=release --enable-languages=c,c++ --disable-multilib

4.3 gcc升级

4.3.1 依赖拉取

cd /apps/scripts/gcc-9.3.0/./contrib/download_prerequisites
// 在gcc-9.3.0目录下，多了gmp-6.1.0.tar.bz2、isl-0.18.tar.bz2、mpc-1.0.3.tar.gz、mpfr-3.1.4.tar.bz2四个压缩文件
// 若已经安装了bzip2命令，则会自动解压上述压缩包
// 演示环境为最小化安装，目前未安装bzip2命令

4.3.2 gmp安装

解压gmp

cd /apps/scripts/gcc-9.3.0/
tar -xvjf gmp-6.1.0.tar.bz2
解压报错：
tar (child): bzip2: Cannot exec: No such file or directory
tar (child): Error is not recoverable: exiting now
tar: Child returned status 2
tar: Error is not recoverable: exiting now

安装bzip2后，重新解压

安装bzip2
yum -y install bzip2 m4
// bzip2：解决上述报错  m4：解决configure过程中报错继续安装gmp
tar -xvjf gmp-6.1.0.tar.bz2
cd /apps/scripts/gcc-9.3.0/gmp-6.1.0
./configure --prefix=/usr/local/gmp-6.1.0
make
make install

解压完成

configure 完成

make完成

make install完成

4.3.3 mpfr安装

cd /apps/scripts/gcc-9.3.0/
tar -xvjf mpfr-3.1.4.tar.bz2
cd mpfr-3.1.4
./configure --prefix=/usr/local/mpfr-3.1.4 --with-gmp=/usr/local/gmp-6.1.0
make
make install

解压完成

configure 完成

make完成

make install 完成

4.3.4 mpc安装

cd /apps/scripts/gcc-9.3.0/
tar -xvf mpc-1.0.3.tar.gz
cd mpc-1.0.3
./configure --prefix=/usr/local/mpc-1.0.3 --with-gmp=/usr/local/gmp-6.1.0 --with-mpfr=/usr/local/mpfr-3.1.4
make
make install

解压完成

configure 完成

make完成

make install 完成

4.3.5 gcc编译、安装

cd /apps/scripts/gcc-9.3.0
mkdir build
cd build/
../configure --prefix=/usr/local/gcc-9.3.0/ --enable-checking=release --enable-languages=c,c++ --disable-multilib --with-gmp=/usr/local/gmp-6.1.0 --with-mpfr=/usr/local/mpfr-3.1.4 --with-mpc=/usr/local/mpc-1.0.3
make
yum -y remove gcc gcc-c++
make install

configure 完成

make完成–很久很久

build目录下对应文件大小

旧版本删除完成

GCC安装完成

4.4 gcc命令配置

ln -s /usr/local/gcc-9.3.0/bin/gcc /usr/bin/gcc
ln -s /usr/local/gcc-9.3.0/bin/g++ /usr/bin/g++
gcc -v