code: func cmdInstall(params Parameters) *subcommands.Command {
  	return &subcommands.Command{
  		Advanced:  true,
  		UsageLine: "install <package> [<version>] [options]",
  		ShortDesc: "installs or updates a package",
  		LongDesc:  "Installs or updates a package.",
  		CommandRun: func() subcommands.CommandRun {
  			c := &installRun{defaultServiceURL: params.ServiceURL}
  			c.registerBaseFlags()
  			c.authFlags.Register(&c.Flags, params.DefaultAuthOptions)
  			c.siteRootOptions.registerFlags(&c.Flags)
  			c.Flags.BoolVar(&c.force, "force", false, "Refetch and reinstall the package even if already installed.")
  			return c
  		},
  	}
  }
docs: ////////////////////////////////////////////////////////////////////////////////
  // 'install' subcommand.