examples/loadables/printenv.c

   1 /*
   2  * printenv -- minimal builtin clone of BSD printenv(1).
   3  *
   4  * usage: printenv [varname]
   5  *
   6  */
   7
   8 /*
   9    Copyright (C) 1999-2009 Free Software Foundation, Inc.
  10
  11    This file is part of GNU Bash.
  12    Bash is free software: you can redistribute it and/or modify
  13    it under the terms of the GNU General Public License as published by
  14    the Free Software Foundation, either version 3 of the License, or
  15    (at your option) any later version.
  16
  17    Bash is distributed in the hope that it will be useful,
  18    but WITHOUT ANY WARRANTY; without even the implied warranty of
  19    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20    GNU General Public License for more details.
  21
  22    You should have received a copy of the GNU General Public License
  23    along with Bash.  If not, see <http://www.gnu.org/licenses/>.
  24 */
  25
  26 #include <config.h>
  27 #include <stdio.h>
  28
  29 #include "builtins.h"
  30 #include "shell.h"
  31 #include "bashgetopt.h"
  32 #include "common.h"
  33
  34 extern char **export_env;
  35
  36 int
  37 printenv_builtin (list)
  38      WORD_LIST *list;
  39 {
  40   register char **envp;
  41   int opt;
  42   SHELL_VAR *var;
  43
  44   reset_internal_getopt ();
  45   while ((opt = internal_getopt (list, "")) != -1)
  46     {
  47       switch (opt)
  48         {
  49         default:
  50           builtin_usage ();
  51           return (EX_USAGE);
  52         }
  53     }
  54   list = loptend;
  55
  56   /* printenv */
  57   if (list == 0)
  58     {
  59       maybe_make_export_env ();         /* this allows minimal code */
  60       for (envp = export_env; *envp; envp++)
  61         printf ("%s\n", *envp);
  62       return (EXECUTION_SUCCESS);
  63     }
  64
  65   /* printenv varname */
  66   var = find_variable (list->word->word);
  67   if (var == 0 || (exported_p (var) == 0))
  68     return (EXECUTION_FAILURE);
  69
  70   if (function_p (var))
  71     print_var_function (var);
  72   else
  73     print_var_value (var, 0);
  74
  75   return (EXECUTION_SUCCESS);
  76 }
  77
  78 char *printenv_doc[] = {
  79         "Display environment.",
  80         "",
  81         "Print names and values of environment variables",
  82         (char *)NULL
  83 };
  84
  85 struct builtin printenv_struct = {
  86         "printenv",
  87         printenv_builtin,
  88         BUILTIN_ENABLED,
  89         printenv_doc,
  90         "printenv [varname]",
  91         0
  92 };