## Copyright (C) 2005-2012 Søren Hauberg
## Copyright (C) 2010 VZLU Prague, a.s.
##
## This file is part of Octave.
##
## Octave is free software; you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 3 of the License, or (at
## your option) any later version.
##
## Octave is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING.  If not, see
## <http://www.gnu.org/licenses/>.

## -*- texinfo -*-
## @deftypefn {Function File} {[@var{status}, @var{output}] =} shell (@var{cmd})
## Undocumented internal function.
## @end deftypefn

function [status, output] = shell (cmd)
  persistent have_sh;

  cmd = strrep (cmd, "\\", "/");
  if (ispc () && ! isunix ())
    if (isempty(have_sh))
      if (system("sh.exe -c \"exit\""))
        have_sh = false;
      else
        have_sh = true;
      endif
    endif
    if (have_sh)
      [status, output] = system (cstrcat ("sh.exe -c \"", cmd, "\""));
    else
      error ("Can not find the command shell");
    endif
  else
    [status, output] = system (cmd);
  endif
endfunction