ANSI plus getopt(3)

[unix-history] / usr / src / usr.bin / printenv / printenv.c

/*
* Copyright (c) 1987 Regents of the University of California.
* All rights reserved.
*
* %sccs.include.redist.c%
*/

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1987 Regents of the University of California.\n\
All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)printenv.c  5.5 (Berkeley) %G%";
#endif /* not lint */

#include <sys/types.h>

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

void    usage __P((void));

/*
* printenv
*
* Bill Joy, UCB
* February, 1979
*/
int
main(argc, argv)
       int argc;
       char *argv[];
{
       extern char **environ;
       register char *cp, **ep;
       register size_t len;
       int ch;

       while ((ch = getopt(argc, argv, "")) != EOF)
               switch(ch) {
               case '?':
               default:
                       usage();
               }
       argc -= optind;
       argv += optind;

       if (argc == 0) {
               for (ep = environ; *ep; ep++)
                       (void)printf("%s\n", *ep);
               exit(0);
       }
       len = strlen(*argv);
       for (ep = environ; *ep; ep++)
               if (!memcmp(*ep, *argv, len)) {
                       cp = *ep + len;
                       if (!*cp || *cp == '=') {
                               (void)printf("%s\n", *cp ? cp + 1 : cp);
                               exit(0);
                       }
               }
       exit(1);
}

void
usage()
{
       (void)fprintf(stderr, "usage: printenv [name]\n");
       exit(1);
}