操作步骤如下：

yum remove -y git  #卸载旧版本Git
yum install -y tk zlib-devel openssl-devel perl cpio expat-devel gettext-devel  asciidoc xmlto autoconf  #安装依赖，否则一路报错....
wget https://www.kernel.org/pub/software/scm/git/git-2.1.2.tar.gz  
tar xf v2.2.1.tar.gz
cd git-2.2.1
make configure 
./configure --prefix=/usr/local/git --with-iconv=/usr/local/libiconv   #添加 iconv 支持
make all doc  #编译并生成帮助文档
make install install-doc install-html #安装程序
echo "export PATH=$PATH:/usr/local/git/bin" >> ~/.bash_profile
echo "export GIT_SSL_NO_VERIFY=1" > ~/.bash_profile     (如果不加入这句会出现fatal Peer certificate cannot be authenticated with known CA certificate)
source ~/.bash_profile
git --version