src/printenv.c

   1 /* printenv -- print all or part of environment
   2    Copyright (C) 1989-1997, 1999 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* Usage: printenv [variable...]
  19
  20    If no arguments are given, print the entire environment.
  21    If one or more variable names are given, print the value of
  22    each one that is set, and nothing for ones that are not set.
  23
  24    Exit status:
  25    0 if all variables specified were found
  26    1 if not
  27
  28    David MacKenzie and Richard Mlynarik */
  29
  30 #include <config.h>
  31 #include <stdio.h>
  32 #include <sys/types.h>
  33 #include <getopt.h>
  34
  35 #include "system.h"
  36 #include "closeout.h"
  37 #include "error.h"
  38 #include "long-options.h"
  39
  40 /* The official name of this program (e.g., no `g' prefix).  */
  41 #define PROGRAM_NAME "printenv"
  42
  43 #define AUTHORS "David MacKenzie and Richard Mlynarik"
  44
  45 /* The name this program was run with. */
  46 char *program_name;
  47
  48 static struct option const long_options[] =
  49 {
  50   {0, 0, 0, 0}
  51 };
  52
  53 extern char **environ;
  54
  55 void
  56 usage (int status)
  57 {
  58   if (status != 0)
  59     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  60              program_name);
  61   else
  62     {
  63       printf (_("Usage: %s [OPTION]... [VARIABLE]...\n"), program_name);
  64       printf (_("\
  65 If no environment VARIABLE specified, print them all.\n\
  66 \n\
  67   --help      display this help and exit\n\
  68   --version   output version information and exit\n"));
  69       puts (_("\nReport bugs to <bug-sh-utils@gnu.org>."));
  70     }
  71   exit (status);
  72 }
  73
  74 int
  75 main (int argc, char **argv)
  76 {
  77   char **env;
  78   char *ep, *ap;
  79   int i;
  80   int matches = 0;
  81   int c;
  82   int exit_status;
  83
  84   program_name = argv[0];
  85   setlocale (LC_ALL, "");
  86   bindtextdomain (PACKAGE, LOCALEDIR);
  87   textdomain (PACKAGE);
  88
  89   parse_long_options (argc, argv, PROGRAM_NAME, GNU_PACKAGE, VERSION,
  90                       AUTHORS, usage);
  91
  92   while ((c = getopt_long (argc, argv, "", long_options, NULL)) != -1)
  93     {
  94       switch (c)
  95         {
  96         case 0:
  97           break;
  98
  99         default:
 100           usage (1);
 101         }
 102     }
 103
 104   if (optind == argc)
 105     {
 106       for (env = environ; *env != NULL; ++env)
 107         puts (*env);
 108       exit_status = 0;
 109     }
 110   else
 111     {
 112       for (i = optind; i < argc; ++i)
 113         {
 114           for (env = environ; *env; ++env)
 115             {
 116               ep = *env;
 117               ap = argv[i];
 118               while (*ep != '\0' && *ap != '\0' && *ep++ == *ap++)
 119                 {
 120                   if (*ep == '=' && *ap == '\0')
 121                     {
 122                       puts (ep + 1);
 123                       ++matches;
 124                       break;
 125                     }
 126                 }
 127             }
 128         }
 129       exit_status = (matches != argc - optind);
 130     }
 131
 132   close_stdout_status (2);
 133
 134   exit (exit_status);
 135 }