xref: /freebsd/usr.bin/printenv/printenv.c (revision 57718be8fa0bd5edc11ab9a72e68cc71982939a6)
1 /*-
2  * Copyright (c) 1987, 1993
3  *	The Regents of the University of California.  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  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #ifndef lint
31 static const char copyright[] =
32 "@(#) Copyright (c) 1987, 1993\n\
33 	The Regents of the University of California.  All rights reserved.\n";
34 #endif /* not lint */
35 
36 #if 0
37 #ifndef lint
38 static char sccsid[] = "@(#)printenv.c	8.2 (Berkeley) 5/4/95";
39 #endif /* not lint */
40 #endif
41 
42 #include <sys/cdefs.h>
43 __FBSDID("$FreeBSD$");
44 
45 #include <sys/types.h>
46 
47 #include <stdlib.h>
48 #include <stdio.h>
49 #include <string.h>
50 #include <unistd.h>
51 
52 void	usage(void);
53 extern char **environ;
54 
55 /*
56  * printenv
57  *
58  * Bill Joy, UCB
59  * February, 1979
60  */
61 int
62 main(int argc, char *argv[])
63 {
64 	char *cp, **ep;
65 	size_t len;
66 	int ch;
67 
68 	while ((ch = getopt(argc, argv, "")) != -1)
69 		switch(ch) {
70 		case '?':
71 		default:
72 			usage();
73 		}
74 	argc -= optind;
75 	argv += optind;
76 
77 	if (argc == 0) {
78 		for (ep = environ; *ep; ep++)
79 			(void)printf("%s\n", *ep);
80 		exit(0);
81 	}
82 	len = strlen(*argv);
83 	for (ep = environ; *ep; ep++)
84 		if (!memcmp(*ep, *argv, len)) {
85 			cp = *ep + len;
86 			if (!*cp || *cp == '=') {
87 				(void)printf("%s\n", *cp ? cp + 1 : cp);
88 				exit(0);
89 			}
90 		}
91 	exit(1);
92 }
93 
94 void
95 usage(void)
96 {
97 	(void)fprintf(stderr, "usage: printenv [name]\n");
98 	exit(1);
99 }
100