printenv.c

#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 rcsid[] = "$OpenBSD: guesswhat.c,v 1.5 2003/06/10 22:20:49 deraadt Exp $";
#endif /* not lint */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int
main(int argc, char *argv[])
{
	extern char **environ;
	char *cp, **ep;
	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);
}