code: func GetVersion() string {
  	if currentGitHead == "" {
  		b, err := ioutil.ReadFile(".git/HEAD")
  
  		if err != nil {
  			currentGitHead = "unknown"
  			return currentGitHead
  		}
  
  		p := refRE.FindStringSubmatch(string(b))
  
  		if len(p) < 2 {
  			currentGitHead = string(b)
  			return currentGitHead
  		}
  
  		b, err = ioutil.ReadFile(".git/" + p[1])
  		if err != nil {
  			currentGitHead = p[1]
  			return currentGitHead
  		}
  
  		currentGitHead = string(b)
  	}
  	return currentGitHead
  }
docs: // GetVersion returns the current HEAD git commit if .git exists