code: func cmdResolve(params Parameters) *subcommands.Command {
  	return &subcommands.Command{
  		UsageLine: "resolve <package or package prefix> [options]",
  		ShortDesc: "returns concrete package instance ID given a version",
  		LongDesc:  "Returns concrete package instance ID given a version.",
  		CommandRun: func() subcommands.CommandRun {
  			c := &resolveRun{}
  			c.registerBaseFlags()
  			c.clientOptions.registerFlags(&c.Flags, params, withoutRootDir)
  			c.Flags.StringVar(&c.version, "version", "<version>", "Package version to resolve.")
  			return c
  		},
  	}
  }
docs: ////////////////////////////////////////////////////////////////////////////////
  // 'resolve' subcommand.