diff --git a/usr.bin/diff/diff.h b/usr.bin/diff/diff.h
--- a/usr.bin/diff/diff.h
+++ b/usr.bin/diff/diff.h
@@ -48,6 +48,7 @@
 #define	D_BRIEF		6	/* Say if the files differ */
 #define	D_GFORMAT	7	/* Diff with defined changed group format */
 #define D_SIDEBYSIDE    8	/* Side by side */
+#define	D_QUIET		9	/* Dont output anything */
 
 #define	D_UNSET		-2
 
diff --git a/usr.bin/diff/diff.c b/usr.bin/diff/diff.c
--- a/usr.bin/diff/diff.c
+++ b/usr.bin/diff/diff.c
@@ -273,7 +273,10 @@
 		case 'q':
 			if (FORMAT_MISMATCHED(D_BRIEF))
 				conflicting_format();
-			diff_format = D_BRIEF;
+			if (diff_format == D_BRIEF)
+				diff_format = D_QUIET;
+			else
+				diff_format = D_BRIEF;
 			break;
 		case 'S':
 			start = optarg;
diff --git a/usr.bin/diff/diffreg.c b/usr.bin/diff/diffreg.c
--- a/usr.bin/diff/diffreg.c
+++ b/usr.bin/diff/diffreg.c
@@ -407,7 +407,8 @@
 		goto closem;
 	}
 
-	if (diff_format == D_BRIEF && ignore_pats == NULL &&
+	if ((diff_format == D_BRIEF || diff_format == D_QUIET) &&
+	    ignore_pats == NULL &&
 	    (flags & (D_FOLDBLANKS|D_IGNOREBLANKS|D_IGNORECASE|
 	    D_SKIPBLANKLINES|D_STRIPCR)) == 0)
 	{
@@ -1094,7 +1095,8 @@
 		return;
 	}
 proceed:
-	if (*pflags & D_HEADER && diff_format != D_BRIEF) {
+	if (*pflags & D_HEADER &&
+	    (diff_format != D_BRIEF && diff_format != D_QUIET)) {
 		printf("%s %s %s\n", diffargs, file1, file2);
 		*pflags &= ~D_HEADER;
 	}
@@ -1142,6 +1144,7 @@
 		anychange = 1;
 	switch (diff_format) {
 	case D_BRIEF:
+	case D_QUIET:
 		return;
 	case D_NORMAL:
 	case D_EDIT: