code: func main() {
  	// Add command names to cfssl usage
  	flag.Usage = nil // this is set to nil for testabilty
  	// Register commands.
  	cmds := map[string]*cli.Command{
  		"bundle":         bundle.Command,
  		"certinfo":       certinfo.Command,
  		"crl":            crl.Command,
  		"sign":           sign.Command,
  		"serve":          serve.Command,
  		"version":        version.Command,
  		"genkey":         genkey.Command,
  		"gencert":        gencert.Command,
  		"gencsr":         gencsr.Command,
  		"gencrl":         gencrl.Command,
  		"ocspdump":       ocspdump.Command,
  		"ocsprefresh":    ocsprefresh.Command,
  		"ocspsign":       ocspsign.Command,
  		"ocspserve":      ocspserve.Command,
  		"selfsign":       selfsign.Command,
  		"scan":           scan.Command,
  		"info":           info.Command,
  		"print-defaults": printdefaults.Command,
  		"revoke":         revoke.Command,
  	}
  
  	// If the CLI returns an error, exit with an appropriate status
  	// code.
  	err := cli.Start(cmds)
  	if err != nil {
  		os.Exit(1)
  	}
  }
docs: // main defines the cfssl usage and registers all defined commands and flags.