Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!clyde!caip!topaz!husc6!seismo!mcvax!guido
From: guido@mcvax.uucp (Guido van Rossum)
Newsgroups: net.unix-wizards,net.unix
Subject: Re: which is my login terminal
Message-ID: <6995@boring.mcvax.UUCP>
Date: Sun, 29-Jun-86 19:46:09 EDT
Article-I.D.: boring.6995
Posted: Sun Jun 29 19:46:09 1986
Date-Received: Fri, 11-Jul-86 04:58:00 EDT
References: <34@gec-rl-hrc.co.uk> <901@isis.UUCP>
Reply-To: guido@boring.uucp (Guido van Rossum)
Organization: "Stamp Out BASIC" Committee, CWI, Amsterdam
Lines: 24
Keywords: sun, control terminal
Xref: watmath net.unix-wizards:18763 net.unix:8553
Apparently-To: rnews@mcvax

In shell scripts, do the following:

	case `tty` in
	/dev/console)	CONSOLE=YES;;
	*)		CONSOLE=NO;;
	esac

The equivalent 'C' code is:

bool on_console() {
	int i;
	/* Search file descriptors 0, 1, 2 for a device name */
	for (i= 0; i <= 2; ++i) {
		char *p= ttyname(i);
		if (p != 0 && strcmp(p, "/dev/console") == 0)
			return YES;
	}
	return NO;
}

Of course this returns NO in a window -- there you can't 'scribble all
over the display' as the original poster asked.

Guido van Rossum, CWI, Amsterdam <guido@mcvax.uucp>