--- a/scripts/general/diff.m
+++ b/scripts/general/diff.m
@@ -1,15 +1,15 @@
 ## Copyright (C) 1995, 1996  Kurt Hornik
-## 
+##
 ## This program 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.
-## 
+##
 ## This program 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. 
-## 
+## General Public License for more details.
+##
 ## You should have received a copy of the GNU General Public License
 ## along with this file.  If not, write to the Free Software Foundation,
 ## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
@@ -26,10 +26,10 @@
 ## @ifinfo
 ##  @var{x}(2) - @var{x}(1), @dots{}, @var{x}(n) - @var{x}(n-1).
 ## @end ifinfo
-## 
+##
 ## If @var{x} is a matrix, @code{diff (@var{x})} is the matrix of column
 ## differences.
-## 
+##
 ## The second argument is optional.  If supplied, @code{diff (@var{x},
 ## @var{k})}, where @var{k} is a nonnegative integer, returns the
 ## @var{k}-th differences.
@@ -40,7 +40,7 @@
 ## Adapted-By: jwe
 
 function x = diff (x, k)
-  
+
   if (nargin == 1)
     k = 1;
   elseif (nargin == 2)
@@ -52,7 +52,7 @@
   else
     usage ("diff (x [, k]");
   endif
-  
+
   if (isstr (x))
     error ("diff: symbolic differentiation not (yet) supported");
   elseif (is_vector (x))
@@ -61,7 +61,7 @@
       x = [];
     else
       for i = 1 : k
-	x = x (2 : (n - i + 1)) - x (1 : (n - i));
+        x = x (2 : (n - i + 1)) - x (1 : (n - i));
       endfor
     endif
   elseif (is_matrix (x))
@@ -70,7 +70,7 @@
       x = [];
     else
       for i = 1 : k
-	x = x (2 : (n - i + 1), :) - x (1: (n - i), :);
+        x = x (2 : (n - i + 1), :) - x (1: (n - i), :);
       endfor
     endif
   else