src/printenv.c

   1 /* printenv -- print all or part of environment
   2    Copyright (C) 1989-1997, 1999-2004 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    2 if some other error occurred
  28
  29    David MacKenzie and Richard Mlynarik */
  30
  31 #include <config.h>
  32 #include <stdio.h>
  33 #include <sys/types.h>
  34 #include <getopt.h>
  35
  36 #include "system.h"
  37 #include "error.h"
  38 #include "long-options.h"
  39
  40 /* Exit status for syntax errors, etc.  */
  41 enum { PRINTENV_FAILURE = 2 };
  42
  43 /* The official name of this program (e.g., no `g' prefix).  */
  44 #define PROGRAM_NAME "printenv"
  45
  46 #define AUTHORS "David MacKenzie", "Richard Mlynarik"
  47
  48 /* The name this program was run with. */
  49 char *program_name;
  50
  51 static struct option const long_options[] =
  52 {
  53   {0, 0, 0, 0}
  54 };
  55
  56 extern char **environ;
  57
  58 void
  59 usage (int status)
  60 {
  61   if (status != EXIT_SUCCESS)
  62     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  63              program_name);
  64   else
  65     {
  66       printf (_("\
  67 Usage: %s [VARIABLE]...\n\
  68   or:  %s OPTION\n\
  69 If no environment VARIABLE specified, print them all.\n\
  70 \n\
  71 "),
  72               program_name, program_name);
  73       fputs (HELP_OPTION_DESCRIPTION, stdout);
  74       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  75       printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
  76     }
  77   exit (status);
  78 }
  79
  80 int
  81 main (int argc, char **argv)
  82 {
  83   char **env;
  84   char *ep, *ap;
  85   int i;
  86   int matches = 0;
  87   int c;
  88   int exit_status;
  89
  90   initialize_main (&argc, &argv);
  91   program_name = argv[0];
  92   setlocale (LC_ALL, "");
  93   bindtextdomain (PACKAGE, LOCALEDIR);
  94   textdomain (PACKAGE);
  95
  96   initialize_exit_failure (PRINTENV_FAILURE);
  97   atexit (close_stdout);
  98
  99   parse_long_options (argc, argv, PROGRAM_NAME, GNU_PACKAGE, VERSION,
 100                       usage, AUTHORS, (char const *) NULL);
 101
 102   while ((c = getopt_long (argc, argv, "", long_options, NULL)) != -1)
 103     {
 104       switch (c)
 105         {
 106         case 0:
 107           break;
 108
 109         default:
 110           usage (PRINTENV_FAILURE);
 111         }
 112     }
 113
 114   if (optind >= argc)
 115     {
 116       for (env = environ; *env != NULL; ++env)
 117         puts (*env);
 118       exit_status = EXIT_SUCCESS;
 119     }
 120   else
 121     {
 122       for (i = optind; i < argc; ++i)
 123         {
 124           for (env = environ; *env; ++env)
 125             {
 126               ep = *env;
 127               ap = argv[i];
 128               while (*ep != '\0' && *ap != '\0' && *ep++ == *ap++)
 129                 {
 130                   if (*ep == '=' && *ap == '\0')
 131                     {
 132                       puts (ep + 1);
 133                       ++matches;
 134                       break;
 135                     }
 136                 }
 137             }
 138         }
 139       exit_status = (matches != argc - optind);
 140     }
 141
 142   exit (exit_status);
 143 }