code: func cmdRegister(params Parameters) *subcommands.Command {
  	return &subcommands.Command{
  		Advanced:  true,
  		UsageLine: "pkg-register <package instance file>",
  		ShortDesc: "uploads and registers package instance in the package repository",
  		LongDesc:  "Uploads and registers package instance in the package repository.",
  		CommandRun: func() subcommands.CommandRun {
  			c := &registerRun{}
  			c.registerBaseFlags()
  			c.Opts.refsOptions.registerFlags(&c.Flags)
  			c.Opts.tagsOptions.registerFlags(&c.Flags)
  			c.Opts.clientOptions.registerFlags(&c.Flags, params, withoutRootDir)
  			c.Opts.uploadOptions.registerFlags(&c.Flags)
  			c.Opts.hashOptions.registerFlags(&c.Flags)
  			return c
  		},
  	}
  }
docs: ////////////////////////////////////////////////////////////////////////////////
  // 'pkg-register' subcommand.