nginx配置做了修改，运行一段时间或者安装了新的程序，都需要重启，网上的很多教程都需要使用脚本或者是

kill -HUP $pid($pid就是nginx master进程的进程号)

研究了一下nginx帮助后发现，有-s参数可对nginx服务进行管理： 
# /usr/local/nginx/sbin/nginx -h 
nginx version: nginx/
Usage: nginx [-?hvVt] [-s signal] [-c filename] [-p prefix] [-g directives]

Options: 
-?,-h : this help 
-v : show version and exit 
-V : show version and configure options then exit 
-t : test configuration and exit 
-s signal : send signal to a master process: stop, quit, reopen, reload 
-p prefix : set prefix path (default: /usr/local/nginx/) 
-c filename : set configuration file (default: conf/nginx.conf) 
-g directives : set global directives out of configuration file

这样执行
# /usr/local/nginx/sbin/nginx -s  reload 
nginx已经重启成功

同样我们可以通过测试配置文件是否正确

# /usr/local/nginx/sbin/nginx -t
the configuration file /usr/local/nginx/conf/nginx.conf syntax is ok
configuration file /usr/local/nginx/conf/nginx.conf test is successful

配置文件正确