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printenv.c revision 1.9.10.1 
      1 /*	$NetBSD: printenv.c,v 1.9.10.1 2010/04/21 05:27:12 matt Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1987, 1993
      5  *    The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #ifndef lint
     34 __COPYRIGHT("@(#) Copyright (c) 1987, 1993\
     35  The Regents of the University of California.  All rights reserved.");
     36 #endif /* not lint */
     37 
     38 #ifndef lint
     39 /*static char sccsid[] = "from: @(#)printenv.c	8.2 (Berkeley) 5/4/95";*/
     40 __RCSID("$NetBSD: printenv.c,v 1.9.10.1 2010/04/21 05:27:12 matt Exp $");
     41 #endif /* not lint */
     42 
     43 #include <sys/types.h>
     44 
     45 #include <stdlib.h>
     46 #include <stdio.h>
     47 #include <string.h>
     48 #include <unistd.h>
     49 #include <err.h>
     50 
     51 int	main __P((int, char **));
     52 void	usage __P((void));
     53 
     54 /*
     55  * printenv
     56  *
     57  * Bill Joy, UCB
     58  * February, 1979
     59  */
     60 int
     61 main(argc, argv)
     62 	int argc;
     63 	char *argv[];
     64 {
     65 	extern char **environ;
     66 	char *cp, **ep;
     67 	size_t len;
     68 	int ch;
     69 
     70 	while ((ch = getopt(argc, argv, "")) != -1)
     71 		switch(ch) {
     72 		case '?':
     73 		default:
     74 			usage();
     75 		}
     76 	argc -= optind;
     77 	argv += optind;
     78 
     79 	if (argc == 0) {
     80 		for (ep = environ; *ep; ep++)
     81 			(void)printf("%s\n", *ep);
     82 		exit(0);
     83 	}
     84 	if (argc != 1)
     85 		usage();
     86 	if (strchr(*argv, '=') != NULL)
     87 		errx(1, "Invalid environment variable %s", *argv);
     88 	len = strlen(*argv);
     89 	for (ep = environ; *ep; ep++)
     90 		if (!memcmp(*ep, *argv, len)) {
     91 			cp = *ep + len;
     92 			if (!*cp || *cp == '=') {
     93 				(void)printf("%s\n", *cp ? cp + 1 : cp);
     94 				exit(0);
     95 			}
     96 		}
     97 	exit(1);
     98 }
     99 
    100 void
    101 usage()
    102 {
    103 	(void)fprintf(stderr, "Usage: printenv [name]\n");
    104 	exit(1);
    105 }
    106