diff --git a/test-sha1.c b/test-sha1.c
index 80daba980..e57eae10b 100644
--- a/test-sha1.c
+++ b/test-sha1.c
@@ -5,10 +5,15 @@ int main(int ac, char **av)
 	git_SHA_CTX ctx;
 	unsigned char sha1[20];
 	unsigned bufsz = 8192;
+	int binary = 0;
 	char *buffer;
 
-	if (ac == 2)
-		bufsz = strtoul(av[1], NULL, 10) * 1024 * 1024;
+	if (ac == 2) {
+		if (!strcmp(av[1], "-b"))
+			binary = 1;
+		else
+			bufsz = strtoul(av[1], NULL, 10) * 1024 * 1024;
+	}
 
 	if (!bufsz)
 		bufsz = 8192;
@@ -42,6 +47,10 @@ int main(int ac, char **av)
 		git_SHA1_Update(&ctx, buffer, this_sz);
 	}
 	git_SHA1_Final(sha1, &ctx);
-	puts(sha1_to_hex(sha1));
+
+	if (binary)
+		fwrite(sha1, 1, 20, stdout);
+	else
+		puts(sha1_to_hex(sha1));
 	exit(0);
 }