报错信息：
user@C02FP58GML7H pbfile % protoc --go_out=./ ./user.proto
protoc-gen-go: program not found or is not executable
Please specify a program using absolute path or make sure the program is available in your PATH system variable
--go_out: protoc-gen-go: Plugin failed with status code 1.
解决办法
- 找到protoc-gen-go 文件，复制文件到
/usr/local/bin/目录下，该文件通过go get安装时会默认安装在$GOPATH/go/bin目录下，博主本人的安装路径/Users/user/go/bin
执行复制命令：cp protoc-gen-go /usr/local/bin/ - 修改环境变量配置：vim ~/.bash_profile
添加：export GOPATH=$HOME/go PATH=$PATH:$GOPATH/bin
刷新环境变量：source ~/.bash_profile
结果示例：
user@C02FP58GML7H bin % vim ~/.bash_profile
user@C02FP58GML7H bin % source ~/.bash_profile
/Users/user/.bash_profile:source:3: no such file or directory: /usr/local/bin/virtualenvwrapper.sh