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printenv.c revision 1.4 
      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 1.4 1993/12/31 19:28:15 jtc Exp $";
     43 #endif /* not lint */
     44 
     45 #include <stdio.h>
     46 #include <string.h>
     47 #include <stdlib.h>
     48 
     49 /*
     50  * printenv
     51  *
     52  * Bill Joy, UCB
     53  * February, 1979
     54  */
     55 int
     56 main(argc, argv)
     57 	int argc;
     58 	char **argv;
     59 {
     60 	extern char **environ;
     61 	register char *cp, **ep;
     62 	register int len;
     63 
     64 	if (argc < 2) {
     65 		for (ep = environ; *ep; ep++)
     66 			puts(*ep);
     67 		exit(0);
     68 	}
     69 	len = strlen(*++argv);
     70 	for (ep = environ; *ep; ep++)
     71 		if (!strncmp(*ep, *argv, len)) {
     72 			cp = *ep + len;
     73 			if (!*cp || *cp == '=') {
     74 				puts(*cp ? cp + 1 : cp);
     75 				exit(0);
     76 			}
     77 		}
     78 	exit(1);
     79 }
     80