xref: /openbsd/usr.bin/printenv/printenv.c (revision 17df1aa7)
1 /*	$OpenBSD: printenv.c,v 1.6 2009/10/27 23:59:41 deraadt Exp $	*/
2 
3 /*
4  * Copyright (c) 1987 Regents of the University of California.
5  * 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 <stdio.h>
33 #include <string.h>
34 #include <stdlib.h>
35 
36 /*
37  * printenv
38  *
39  * Bill Joy, UCB
40  * February, 1979
41  */
42 int
43 main(int argc, char *argv[])
44 {
45 	extern char **environ;
46 	char *cp, **ep;
47 	int len;
48 
49 	if (argc < 2) {
50 		for (ep = environ; *ep; ep++)
51 			puts(*ep);
52 		exit(0);
53 	}
54 	len = strlen(*++argv);
55 	for (ep = environ; *ep; ep++)
56 		if (!strncmp(*ep, *argv, len)) {
57 			cp = *ep + len;
58 			if (!*cp || *cp == '=') {
59 				puts(*cp ? cp + 1 : cp);
60 				exit(0);
61 			}
62 		}
63 	exit(1);
64 }
65