xref: /netbsd-src/usr.bin/printenv/printenv.c (revision 4b30c543a0b21e3ba94f2c569e9a82b4fdb2075f)
1 /*
2  * Copyright (c) 1987 Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #ifndef lint
35 char copyright[] =
36 "@(#) Copyright (c) 1987 Regents of the University of California.\n\
37  All rights reserved.\n";
38 #endif /* not lint */
39 
40 #ifndef lint
41 /*static char sccsid[] = "from: @(#)printenv.c	5.4 (Berkeley) 6/1/90";*/
42 static char rcsid[] = "$Id: printenv.c,v 1.3 1993/08/27 22:30:40 jtc Exp $";
43 #endif /* not lint */
44 
45 #include <stdio.h>
46 #include <string.h>
47 
48 /*
49  * printenv
50  *
51  * Bill Joy, UCB
52  * February, 1979
53  */
54 int
55 main(argc, argv)
56 	int argc;
57 	char **argv;
58 {
59 	extern char **environ;
60 	register char *cp, **ep;
61 	register int len;
62 
63 	if (argc < 2) {
64 		for (ep = environ; *ep; ep++)
65 			puts(*ep);
66 		exit(0);
67 	}
68 	len = strlen(*++argv);
69 	for (ep = environ; *ep; ep++)
70 		if (!strncmp(*ep, *argv, len)) {
71 			cp = *ep + len;
72 			if (!*cp || *cp == '=') {
73 				puts(*cp ? cp + 1 : cp);
74 				exit(0);
75 			}
76 		}
77 	exit(1);
78 }
79