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printenv.c revision 1.1.1.2 
      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  * 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 static char copyright[] =
     36 "@(#) Copyright (c) 1987, 1993\n\
     37 	The Regents of the University of California.  All rights reserved.\n";
     38 #endif /* not lint */
     39 
     40 #ifndef lint
     41 static char sccsid[] = "@(#)printenv.c	8.2 (Berkeley) 5/4/95";
     42 #endif /* not lint */
     43 
     44 #include <sys/types.h>
     45 
     46 #include <stdlib.h>
     47 #include <stdio.h>
     48 #include <string.h>
     49 #include <unistd.h>
     50 
     51 void	usage __P((void));
     52 
     53 /*
     54  * printenv
     55  *
     56  * Bill Joy, UCB
     57  * February, 1979
     58  */
     59 int
     60 main(argc, argv)
     61 	int argc;
     62 	char *argv[];
     63 {
     64 	extern char **environ;
     65 	register char *cp, **ep;
     66 	register size_t len;
     67 	int ch;
     68 
     69 	while ((ch = getopt(argc, argv, "")) != EOF)
     70 		switch(ch) {
     71 		case '?':
     72 		default:
     73 			usage();
     74 		}
     75 	argc -= optind;
     76 	argv += optind;
     77 
     78 	if (argc == 0) {
     79 		for (ep = environ; *ep; ep++)
     80 			(void)printf("%s\n", *ep);
     81 		exit(0);
     82 	}
     83 	len = strlen(*argv);
     84 	for (ep = environ; *ep; ep++)
     85 		if (!memcmp(*ep, *argv, len)) {
     86 			cp = *ep + len;
     87 			if (!*cp || *cp == '=') {
     88 				(void)printf("%s\n", *cp ? cp + 1 : cp);
     89 				exit(0);
     90 			}
     91 		}
     92 	exit(1);
     93 }
     94 
     95 void
     96 usage()
     97 {
     98 	(void)fprintf(stderr, "usage: printenv [name]\n");
     99 	exit(1);
    100 }
    101