From f54c7b4cac5c5ff3251828691a475e40b4f9cb0e Mon Sep 17 00:00:00 2001
From: sin <sin@2f30.org>
Date: Mon, 7 Oct 2013 15:50:41 +0100
Subject: [PATCH] Simplify tty(1)

Add a usage line and print "not a tty" for all error cases.
---
 tty.c | 32 +++++++++++++++++---------------
 1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/tty.c b/tty.c
index fcdb21b..6bb77ae 100644
--- a/tty.c
+++ b/tty.c
@@ -1,24 +1,26 @@
 /* See LICENSE file for copyright and license details. */
-#include <errno.h>
+#include <unistd.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <unistd.h>
+#include "util.h"
+
+static void
+usage(void)
+{
+	eprintf("usage: %s\n", argv0);
+}
 
 int
-main(void)
+main(int argc, char *argv[])
 {
 	char *tty;
 
-	if((tty = ttyname(STDIN_FILENO))) {
-		puts(tty);
-		return 0;
-	}
-	else if(errno == ENOTTY) {
-		puts("not a tty");
-		return 1;
-	}
-	else {
-		perror("ttyname");
-		return 2;
-	}
+	ARGBEGIN {
+	default:
+		usage();
+	} ARGEND;
+
+	tty = ttyname(STDIN_FILENO);
+	puts(tty ? tty : "not a tty");
+	return tty ? 0 : 1;
 }