以下来自官网文档:http://nginx.org/en/linux_packages.html
cat >/etc/yum.repos.d/nginx.repo<<EOF
[nginx]
name=nginx repo
baseurl=http://nginx.org/packages/centos/6/\$basearch/
# baseurl=http://nginx.org/packages/centos/7/\$basearch/
# baseurl=http://nginx.org/packages/rhel/6/\$basearch/
# baseurl=http://nginx.org/packages/rhel/7/\$basearch/
gpgcheck=0
enabled=1
EOF
# 根据发行版选择centos或者rhel,根据系统大版本选择6或者7
yum -y install nginx