diff -r 684599feaa5c sys/src/cmd/tee.c
--- a/sys/src/cmd/tee.c	Fri Feb 08 22:28:20 2019 +0100
+++ b/sys/src/cmd/tee.c	Sun Feb 10 20:25:45 2019 -0600
@@ -9,7 +9,6 @@
 	FDSTART = 3,
 };
 
-int	uflag;
 int	aflag;
 
 char in[8192];
@@ -31,11 +30,6 @@
 		atnotify(intignore, 1);
 		break;
 
-	case 'u':
-		uflag++;
-		/* uflag is ignored and undocumented; it's a relic from Unix */
-		break;
-
 	default:
 		fprint(2, "usage: tee [-ai] [file ...]\n");
 		exits("usage");