1.查看开机自启项
centos7自启项已不用chkconfig改为：
systemctl list-unit-files
左边是服务名称，右边是状态，enabled是开机启动，disabled是开机不启动。
当然还可以过滤一下 比如：查看启动项
systemctl list-unit-files | grep enable
2.设置开机自启项
systemctl enable redis
systemctl enable nginx.service
启动nginx
systemctl start nginx.service
结束nginx
systemctl stop nginx.service
重启nginx
systemctl restart nginx.service