--- a/scripts/control/system/__sysconcat__.m
+++ b/scripts/control/system/__sysconcat__.m
@@ -1,23 +1,44 @@
-function c = __sysconcat__(a,b)
-  # c = __sysconcat__(a,b)
-  # cell array replacement for append, used by control systems toolbox
+## Copyright (C) 1996, 1998 Auburn University.  All rights reserved.
+##
+## 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 2, 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, write to the Free
+## Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+## 02110-1301 USA.
 
-  if(ischar(a))
+## Undocumented internal function.
+
+function c = __sysconcat__ (a, b)
+
+  ## c = __sysconcat__ (a, b)
+  ## cell array replacement for append, used by control systems toolbox
+
+  if (ischar (a))
     a = {a};
   endif
-  if(ischar(b))
+  if (ischar (b))
     b = {b};
   endif
 
-  if ( ! ( is_signal_list(a)  && is_signal_list(b) ) )
+  if (! (is_signal_list (a) && is_signal_list (b)))
     error("need cell arrays of strings");
   endif
 
   c = a;
-  la = length(a);
-  for ii=1:length(b)
+  la = length (a);
+  for ii = 1:length (b)
     c{la+ii} = b{ii};
   endfor
 
 endfunction
-