4.3BSD-Reno/src/usr.bin/tty/tty.c

/*
 * Copyright (c) 1988 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that: (1) source distributions retain this entire copyright
 * notice and comment, and (2) distributions including binaries display
 * the following acknowledgement:  ``This product includes software
 * developed by the University of California, Berkeley and its contributors''
 * in the documentation or other materials provided with the distribution
 * and in all advertising materials mentioning features or use of this
 * software. Neither the name of the University nor the names of its
 * contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1988 Regents of the University of California.\n\
 All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)tty.c	4.4 (Berkeley) 6/1/90";
#endif /* not lint */

#include <stdio.h>

main(argc, argv)
	int argc;
	char **argv;
{
	int ch, sflag;
	char *t, *ttyname();

	sflag = 0;
	while ((ch = getopt(argc, argv, "s")) != EOF)
		switch((char)ch) {
		case 's':
			sflag = 1;
			break;
		case '?':
		default:
			fputs("usage: tty [-s]\n", stderr);
			exit(2);
		}

	t = ttyname(0);
	if (!sflag)
		puts(t ? t : "not a tty");
	exit(t ? 0 : 1);
}