1. 先下载相关的 deb 包，我通过一台新的Ubuntu机子下载好相关的包，点击下载
2. 将下载好的压缩包上传到服务器上，解压缩
unzip gcc.zip
cd gcc由于我自己是把这些deb包上传到我自己的源上，所以就没用 dpkg 安装了。
不过根据 apt-get install gcc 提示
Setting up gcc-7-base:amd64 (7.3.0-27ubuntu1~18.04) ...
Setting up binutils-common:amd64 (2.30-21ubuntu1~18.04) ...
Setting up libbinutils:amd64 (2.30-21ubuntu1~18.04) ...
Setting up binutils-x86-64-linux-gnu (2.30-21ubuntu1~18.04) ...
Setting up binutils (2.30-21ubuntu1~18.04) ...
Setting up libisl19:amd64 (0.19-1) ...
Setting up libmpfr6:amd64 (4.0.1-1) ...
Setting up libmpc3:amd64 (1.1.0-1) ...
Setting up cpp-7 (7.3.0-27ubuntu1~18.04) ...
Setting up cpp (4:7.3.0-3ubuntu2.1) ...
Setting up libcc1-0:amd64 (8.2.0-1ubuntu2~18.04) ...
Setting up libgomp1:amd64 (8.2.0-1ubuntu2~18.04) ...
Setting up libitm1:amd64 (8.2.0-1ubuntu2~18.04) ...
Setting up libatomic1:amd64 (8.2.0-1ubuntu2~18.04) ...
Setting up libasan4:amd64 (7.3.0-27ubuntu1~18.04) ...
Setting up liblsan0:amd64 (8.2.0-1ubuntu2~18.04) ...
Setting up libtsan0:amd64 (8.2.0-1ubuntu2~18.04) ...
Setting up libubsan0:amd64 (7.3.0-27ubuntu1~18.04) ...
Setting up libcilkrts5:amd64 (7.3.0-27ubuntu1~18.04) ...
Setting up libmpx2:amd64 (8.2.0-1ubuntu2~18.04) ...
Setting up libquadmath0:amd64 (8.2.0-1ubuntu2~18.04) ...
Setting up libgcc-7-dev:amd64 (7.3.0-27ubuntu1~18.04) ...
Setting up gcc-7 (7.3.0-27ubuntu1~18.04) ...
Setting up gcc (4:7.3.0-3ubuntu2.1) ...
可以根据这个提示，找到相关的包，依次安装。（如有问题，请留言^^）
最后，试试有没有安装成功：
gcc -v