/System/Library/LaunchDaemons/org.apache.httpd.plist: service already loaded
Load failed: 37: Operation already in progress
更新MacOS 10.12 系统后，在终端里启动apache时都会提示.
取消开机自启
sudo launchctl unload -w /System/Library/LaunchDaemons/org.apache.httpd.plist
打开开机自启
sudo launchctl load -w /System/Library/LaunchDaemons/org.apache.httpd.plist
launchd是Mac OS下，用于初始化系统环境的关键进程。类似Linux下的init, rc.此方法同样也适用于禁用系统的一些服务,比如打印机,蓝牙等