src/printenv.c

   1 /* printenv -- print all or part of environment
   2    Copyright (C) 1989-1997, 1999, 2000, 2001 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 N_ ("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 (_("\
  64 Usage: %s [VARIABLE]...\n\
  65   or:  %s OPTION\n\
  66 If no environment VARIABLE specified, print them all.\n\
  67 \n\
  68 "),
  69               program_name, program_name);
  70       fputs (HELP_OPTION_DESCRIPTION, stdout);
  71       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  72       printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
  73     }
  74   exit (status);
  75 }
  76
  77 int
  78 main (int argc, char **argv)
  79 {
  80   char **env;
  81   char *ep, *ap;
  82   int i;
  83   int matches = 0;
  84   int c;
  85   int exit_status;
  86
  87   program_name = argv[0];
  88   setlocale (LC_ALL, "");
  89   bindtextdomain (PACKAGE, LOCALEDIR);
  90   textdomain (PACKAGE);
  91
  92   close_stdout_set_status (2);
  93   atexit (close_stdout);
  94
  95   parse_long_options (argc, argv, PROGRAM_NAME, GNU_PACKAGE, VERSION,
  96                       AUTHORS, usage);
  97
  98   while ((c = getopt_long (argc, argv, "", long_options, NULL)) != -1)
  99     {
 100       switch (c)
 101         {
 102         case 0:
 103           break;
 104
 105         default:
 106           usage (1);
 107         }
 108     }
 109
 110   if (optind == argc)
 111     {
 112       for (env = environ; *env != NULL; ++env)
 113         puts (*env);
 114       exit_status = 0;
 115     }
 116   else
 117     {
 118       for (i = optind; i < argc; ++i)
 119         {
 120           for (env = environ; *env; ++env)
 121             {
 122               ep = *env;
 123               ap = argv[i];
 124               while (*ep != '\0' && *ap != '\0' && *ep++ == *ap++)
 125                 {
 126                   if (*ep == '=' && *ap == '\0')
 127                     {
 128                       puts (ep + 1);
 129                       ++matches;
 130                       break;
 131                     }
 132                 }
 133             }
 134         }
 135       exit_status = (matches != argc - optind);
 136     }
 137
 138   exit (exit_status);
 139 }