--- a/scripts/control/lyap.m
+++ b/scripts/control/lyap.m
@@ -1,48 +1,49 @@
-# Copyright (C) 1996 John W. Eaton
-# 
-# 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, 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+### Copyright (C) 1996 John W. Eaton
+###
+### 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, 59 Temple Place - Suite 330, Boston, MA
+### 02111-1307, USA.
 
 function x = lyap (a, b, c)
 
-# Usage: x = lyap (a, b {,c})
-#
-# If (a, b, c) are specified, then lyap returns the solution of the
-# Sylvester equation
-#
-#   a x + x b + c = 0
-#
-# If only (a, b) are specified, then lyap returns the solution of the 
-# Lyapunov equation
-#
-#   a' x + x a + b = 0
-#
-# If b is not square, then lyap returns the solution of either
-#
-#   a' x + x a + b' b = 0 	
-#
-# or
-#
-#   a x + x a' + b b' = 0
-#
-# whichever is appropriate.
-#
-# Solves by using the Bartels-Stewart algorithm (1972).
+  ## Usage: x = lyap (a, b {,c})
+  ##
+  ## If (a, b, c) are specified, then lyap returns the solution of the
+  ## Sylvester equation
+  ##
+  ##   a x + x b + c = 0
+  ##
+  ## If only (a, b) are specified, then lyap returns the solution of the 
+  ## Lyapunov equation
+  ##
+  ##   a' x + x a + b = 0
+  ##
+  ## If b is not square, then lyap returns the solution of either
+  ##
+  ##   a' x + x a + b' b = 0 	
+  ##
+  ## or
+  ##
+  ##   a x + x a' + b b' = 0
+  ##
+  ## whichever is appropriate.
+  ##
+  ## Solves by using the Bartels-Stewart algorithm (1972).
 
-# Written by A. S. Hodel (scotte@eng.auburn.edu) August 1993.
+  ## Written by A. S. Hodel (scotte@eng.auburn.edu) August 1993.
   
 
   if (nargin != 3 && nargin != 2)
@@ -55,18 +56,18 @@
 
   if (nargin == 2)
 
-# Transform Lyapunov equation to Sylvester equation form.
+    ## Transform Lyapunov equation to Sylvester equation form.
 
     if ((m = is_square (b)) == 0)
       if ((m = rows (b)) == n)
 
-# solve a x + x a' + b b' = 0
+	## solve a x + x a' + b b' = 0
 
 	b = b * b';
 	a = a';
       else 
 
-# Try to solve a'x + x a + b' b = 0.
+	## Try to solve a'x + x a + b' b = 0.
 
 	m = columns (b);
 	b = b' * b;
@@ -77,7 +78,7 @@
       endif
     endif
 
-# Set up Sylvester equation.
+    ## Set up Sylvester equation.
 
     c = b;
     b = a;
@@ -85,7 +86,7 @@
 
   else 
 
-# Check dimensions.
+    ## Check dimensions.
 
     if ((m = is_square (b)) == 0)
       error ("lyap: b must be square in a sylvester equation");
@@ -98,7 +99,7 @@
     endif
   endif
 
-# Call octave built-in function.
+  ## Call octave built-in function.
 
   x = syl (a, b, c);