protoc-gen-go: program not found or code example

Example: 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.

export GOROOT=/usr/local/go
export GOPATH=$HOME/go
export GOBIN=$GOPATH/bin
export PATH=$PATH:$GOROOT:$GOPATH:$GOBIN