change oizys update

pkgs/oizys/cmd/update.go

@@ -16,24 +16,29 @@ var updateCmd = &cobra.Command{
 	Short: "update and run nixos rebuild",
 	Run: func(cmd *cobra.Command, args []string) {
 		run := github.GetLastUpdateRun()
-		if preview {
 		md, err := github.GetUpateSummary(run.GetID())
 		if err != nil {
 			log.Fatal(err)
 		}
 		fmt.Println(md)
-			if !ui.Confirm("proceed with system update?") {
+		if preview {
 			os.Exit(0)
 		}
+		if !yes && !ui.Confirm("proceed with system update?") {
+			os.Exit(0)
 		}
 		oizys.UpdateRepo()
 		oizys.NixosRebuild("switch")
 	},
 }
 
-var preview bool
+var (
+	preview bool
+	yes     bool
+)
 
 func init() {
 	rootCmd.AddCommand(updateCmd)
 	updateCmd.Flags().BoolVar(&preview, "preview", false, "confirm nix store diff")
+	updateCmd.Flags().BoolVar(&yes, "yes", false, "reply yes to all confirm prompts")
 }