code: func cmdFetch(params Parameters) *subcommands.Command {
  	return &subcommands.Command{
  		Advanced:  true,
  		UsageLine: "pkg-fetch <package> [options]",
  		ShortDesc: "fetches a package instance file from the repository",
  		LongDesc:  "Fetches a package instance file from the repository.",
  		CommandRun: func() subcommands.CommandRun {
  			c := &fetchRun{}
  			c.registerBaseFlags()
  			c.clientOptions.registerFlags(&c.Flags, params, withoutRootDir)
  			c.Flags.StringVar(&c.version, "version", "<version>", "Package version to fetch.")
  			c.Flags.StringVar(&c.outputPath, "out", "<path>", "Path to a file to write fetch to.")
  			return c
  		},
  	}
  }
docs: ////////////////////////////////////////////////////////////////////////////////
  // 'pkg-fetch' subcommand.