support/printenv.c

   1 /* printenv -- minimal clone of BSD printenv(1).
   2
   3    usage: printenv [varname]
   4
   5    Chet Ramey
   6    chet@po.cwru.edu
   7 */
   8
   9 /* Copyright (C) 1997-2002 Free Software Foundation, Inc.
  10
  11    This file is part of GNU Bash, the Bourne Again SHell.
  12
  13    Bash is free software: you can redistribute it and/or modify
  14    it under the terms of the GNU General Public License as published by
  15    the Free Software Foundation, either version 3 of the License, or
  16    (at your option) any later version.
  17
  18    Bash is distributed in the hope that it will be useful,
  19    but WITHOUT ANY WARRANTY; without even the implied warranty of
  20    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21    GNU General Public License for more details.
  22
  23    You should have received a copy of the GNU General Public License
  24    along with Bash.  If not, see <http://www.gnu.org/licenses/>.
  25 */
  26
  27 #if defined (HAVE_CONFIG_H)
  28 #  include  <config.h>
  29 #endif
  30
  31 #include "bashansi.h"
  32 #include <stdio.h>              /* puts */
  33
  34 extern char **environ;
  35
  36 int
  37 main (argc, argv)
  38      int argc;
  39      char **argv;
  40 {
  41   register char **envp, *eval;
  42   int len;
  43
  44   argv++;
  45   argc--;
  46
  47   /* printenv */
  48   if (argc == 0)
  49     {
  50       for (envp = environ; *envp; envp++)
  51         puts (*envp);
  52       exit (0);
  53     }
  54
  55   /* printenv varname */
  56   len = strlen (*argv);
  57   for (envp = environ; *envp; envp++)
  58     {
  59       if (**argv == **envp && strncmp (*envp, *argv, len) == 0)
  60         {
  61           eval = *envp + len;
  62           /* If the environment variable doesn't have an `=', ignore it. */
  63           if (*eval == '=')
  64             {
  65               puts (eval + 1);
  66               exit (0);
  67             }
  68         }
  69     }
  70   exit (1);
  71 }
  72