restore: add --delete option to remove files that are not in snapshot

cmd/restic/cmd_restore.go

@@ -51,6 +51,7 @@ type RestoreOptions struct {
 	Sparse    bool
 	Verify    bool
 	Overwrite restorer.OverwriteBehavior
+	Delete    bool
 }
 
 var restoreOptions RestoreOptions
@@ -69,6 +70,7 @@ func init() {
 	flags.BoolVar(&restoreOptions.Sparse, "sparse", false, "restore files as sparse")
 	flags.BoolVar(&restoreOptions.Verify, "verify", false, "verify restored files content")
 	flags.Var(&restoreOptions.Overwrite, "overwrite", "overwrite behavior, one of (always|if-changed|if-newer|never) (default: always)")
+	flags.BoolVar(&restoreOptions.Delete, "delete", false, "delete files from target directory if they do not exist in snapshot. Use '--dry-run -vv' to check what would be deleted")
 }
 
 func runRestore(ctx context.Context, opts RestoreOptions, gopts GlobalOptions,
@@ -149,6 +151,7 @@ func runRestore(ctx context.Context, opts RestoreOptions, gopts GlobalOptions,
 		Sparse:    opts.Sparse,
 		Progress:  progress,
 		Overwrite: opts.Overwrite,
+		Delete:    opts.Delete,
 	})
 
 	totalErrors := 0