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

/*
 * Copyright (c) 1987 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) 1987 Regents of the University of California.\n\
 All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)printenv.c	5.4 (Berkeley) 6/1/90";
#endif /* not lint */

/*
 * printenv
 *
 * Bill Joy, UCB
 * February, 1979
 */
main(argc, argv)
	int argc;
	char **argv;
{
	extern char **environ;
	register char *cp, **ep;
	register int len;

	if (argc < 2) {
		for (ep = environ; *ep; ep++)
			puts(*ep);
		exit(0);
	}
	len = strlen(*++argv);
	for (ep = environ; *ep; ep++)
		if (!strncmp(*ep, *argv, len)) {
			cp = *ep + len;
			if (!*cp || *cp == '=') {
				puts(*cp ? cp + 1 : cp);
				exit(0);
			}
		}
	exit(1);
}