diff --git a/bin/pt-diskstats b/bin/pt-diskstats
index f02dedfa..7571a1df 100755
--- a/bin/pt-diskstats
+++ b/bin/pt-diskstats
@@ -1,4 +1,4 @@
-#!/usr/bin/env   perl 
+#!/usr/bin/env perl 
 
 # This program is part of Percona Toolkit: http://www.percona.com/software/
 # See "COPYRIGHT, LICENSE, AND WARRANTY" at the end of this file for legal
@@ -6,13 +6,22 @@
 
 use strict;
 use warnings FATAL => 'all';
-use constant PTDEBUG => $ENV{PTDEBUG} || 0;
 
-# %INC magic to allow us to require/use these even within the big file.
+# This tool is "fat-packed": most of its dependent modules are embedded
+# in this file.  Setting %INC to this file for each module makes Perl aware
+# of this so it will not try to load the module from @INC.  See the tool's
+# documentation for a full list of dependencies.
 BEGIN {
-   $INC{$_} = __FILE__ for map {
-         (my $t = $_ . ".pm") =~ s!::!/!g; $t
-      } qw( OptionParser Transformers ReadKeyMini Diskstats DiskstatsGroupByAll DiskstatsGroupByDisk DiskstatsGroupBySample DiskstatsMenu pt_diskstats );
+   $INC{$_} = __FILE__ for map { (my $pkg = "$_.pm") =~ s!::!/!g; $pkg } (qw(
+      OptionParser
+      Transformers
+      ReadKeyMini
+      Diskstats
+      DiskstatsGroupByAll
+      DiskstatsGroupByDisk
+      DiskstatsGroupBySample
+      DiskstatsMenu
+   ));
 }
 
 # ###########################################################################
diff --git a/lib/Percona/Toolkit.pm b/lib/Percona/Toolkit.pm
new file mode 100644
index 00000000..d48e8319
--- /dev/null
+++ b/lib/Percona/Toolkit.pm
@@ -0,0 +1,47 @@
+# This program is copyright 2012 Percona Inc.
+# Feedback and improvements are welcome.
+#
+# THIS PROGRAM IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
+# WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
+# MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+#
+# 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, version 2; OR the Perl Artistic License.  On UNIX and similar
+# systems, you can issue `man perlgpl' or `man perlartistic' to read these
+# licenses.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+# Place, Suite 330, Boston, MA  02111-1307  USA.
+# ###########################################################################
+# Percona::Toolkit package
+# ###########################################################################
+{
+package Percona::Toolkit;
+
+our $VERSION = '2.1.3';
+
+use strict;
+use warnings FATAL => 'all';
+use English qw(-no_match_vars);
+use constant PTDEBUG => $ENV{PTDEBUG} || 0;
+
+require Exporter;
+our @ISA         = qw(Exporter);
+our %EXPORT_TAGS = ();
+our @EXPORT      = (qw(_d));
+
+sub _d {
+   my ($package, undef, $line) = caller 0;
+   @_ = map { (my $temp = $_) =~ s/\n/\n# /g; $temp; }
+        map { defined $_ ? $_ : 'undef' }
+        @_;
+   print STDERR "# $package:$line $PID ", join(' ', @_), "\n";
+}
+
+1;
+}
+# ###########################################################################
+# End Percona::Toolkit package
+# ###########################################################################
diff --git a/util/tool-header b/util/tool-header
new file mode 100755
index 00000000..abd596ed
--- /dev/null
+++ b/util/tool-header
@@ -0,0 +1,89 @@
+#!/usr/bin/env bash
+
+# This script prints the standard header that should be at the start
+# of every Perl tool.
+
+# ############################################################################
+# Standard startup, find the branch's root directory
+# ############################################################################
+
+exit_status=0
+
+die() {
+   echo $1  >&2
+   exit 1
+}
+
+warn() {
+   echo $1 >&2
+   exit_status=$((exit_status | 1))
+}
+
+cwd="$PWD"
+if [ -n "$PERCONA_TOOLKIT_BRANCH" ]; then
+   BRANCH=$PERCONA_TOOLKIT_BRANCH
+else
+   while [ ! -f Makefile.PL ] && [ $(pwd) != "/" ]; do
+      cd ..
+   done
+   if [ ! -f Makefile.PL ]; then
+      die "Cannot find the root directory of the Percona Toolkit branch"
+   fi
+   BRANCH=`pwd`
+fi
+cd "$cwd"
+
+# ############################################################################
+# Global variables
+# ############################################################################
+
+EXIT_STATUS=0
+
+# ############################################################################
+# Subroutines
+# ############################################################################
+
+# None
+
+# ############################################################################
+# Script starts here
+# ############################################################################
+
+tool_file=$1
+
+if [ -z "$tool_file" ]; then
+   die "Usage: $0 TOOL"
+fi
+
+if [ ! -f $tool_file ]; then
+   die "$tool_file does not exist"
+fi
+
+if ! grep -m 1 -q '^use ' $tool_file; then
+   die "This only works for Perl tools"
+fi
+
+echo "#!/usr/bin/env perl 
+
+# This program is part of Percona Toolkit: http://www.percona.com/software/
+# See \"COPYRIGHT, LICENSE, AND WARRANTY\" at the end of this file for legal
+# notices and disclaimers.
+
+use strict;
+use warnings FATAL => 'all';
+
+# This tool is \"fat-packed\": most of its dependent modules are embedded
+# in this file.  Setting %INC to this file for each module makes Perl aware
+# of this so it will not try to load the module from @INC.  See the tool's
+# documentation for a full list of dependencies.
+BEGIN {
+   \$INC{\$_} = __FILE__ for map { (my \$pkg = \"\$_.pm\") =~ s!::!/!g; \$pkg } (qw(" 
+
+for pkg in $(grep '^package [A-Za-z:]*;' $tool_file | cut -d' ' -f2 | cut -d';' -f1); do
+   echo "      $pkg"
+done
+
+echo "   ));
+}";
+
+exit $EXIT_STATUS
diff --git a/util/update-modules b/util/update-modules
index 37628dc7..d568c9f3 100755
--- a/util/update-modules
+++ b/util/update-modules
@@ -4,7 +4,7 @@
 # Standard startup, find the branch's root directory
 # ############################################################################
 
-exit_status=0
+EXIT_STATUS=0
 
 die() {
    echo $1  >&2
@@ -13,7 +13,7 @@ die() {
 
 warn() {
    echo $1 >&2
-   exit_status=$((exit_status | 1))
+   EXIT_STATUS=$((EXIT_STATUS | 1))
 }
 
 cwd="$PWD"
@@ -34,25 +34,16 @@ cd "$cwd"
 # Global variables
 # ############################################################################
 
-CHECK=${CHECK:-1}
+# None
 
 # ############################################################################
 # Subroutines
 # ############################################################################
 
-file_is_modified() {
-   local file=$1
-   if [ $CHECK -eq 1 ]; then
-      bzr status $file | grep -q modified
-   else
-      return 1
-   fi
-}
-
 pkgs_in_tool() {
    local tool=$1
    if [ "$tool_lang" = "perl" ]; then
-      pkgs=$(grep '^package [A-Za-z]*;' $tool | cut -d' ' -f2 | cut -d';' -f1)
+      pkgs=$(grep '^package [A-Za-z:]*;' $tool | cut -d' ' -f2 | cut -d';' -f1)
    else
       pkgs=$(grep '^# [a-z_]* package' $tool | awk '{print $2}')
    fi
@@ -82,8 +73,8 @@ replace_pkg_in_tool() {
       echo "# $pkg package
 # This package is a copy without comments from the original.  The original
 # with comments and its test file can be found in the Bazaar repository at,
-#   lib/$pkg.pm
-#   t/lib/$pkg.t
+#   lib/$pkg_file_base.pm
+#   t/lib/$pkg_file_base.t
 # See https://launchpad.net/percona-toolkit for more information.
 # ###########################################################################
 {" >> $tmp_file
@@ -108,10 +99,29 @@ echo "# ########################################################################
 # End $pkg package" >> $tmp_file
 
    tail -n +$pkg_end_line  $tool_file >> $tmp_file
-
+ 
    mv $tmp_file $tool_file
 } 
 
+update_tool_header() {
+   local tool_file=$1
+
+   local start_line=$(grep -m 1 -n "^# ###" $tool_file | cut -d':' -f1)
+   if [ -z "$start_line" ]; then
+      warn "$tool_file does not have a package header line"
+      return 1
+   fi
+   start_line=$((start_line - 1))
+
+   tail -n +$start_line $tool_file > $tool_file-code
+   $BRANCH/util/tool-header $tool_file > $tool_file-header
+   if [ $? -ne 0 ]; then
+      warn "Failed to update tool header for $tool_file"
+      return 1
+   fi
+   cat $tool_file-header $tool_file-code > $tool_file
+}
+
 # ############################################################################
 # Script starts here
 # ############################################################################
@@ -119,7 +129,7 @@ echo "# ########################################################################
 tool_file=$1
 
 if [ -z "$tool_file" ]; then
-   die "Usage: $0 TOOL [MODULE...]"
+   die "Usage: $0 TOOL [MODULES]"
 fi
 
 if [ ! -f $tool_file ]; then
@@ -150,7 +160,10 @@ for pkg in $pkgs; do
    fi
 
    if [ "$tool_lang" = "perl" ]; then
+      # Perl :: package separators translate to directory slashes.
       pkg_file="$BRANCH/lib/$pkg.pm"
+      pkg_file=${pkg_file//"::"/"/"}
+      pkg_file_base=${pkg//"::"/"/"}
    else
       pkg_file="$BRANCH/lib/bash/$pkg.sh"
    fi
@@ -160,11 +173,6 @@ for pkg in $pkgs; do
       continue
    fi
 
-   # if file_is_modified $pkg_file; then
-      # warn "$pkg_file has uncommitted changes"
-      # continue
-   # fi 
-
    replace_pkg_in_tool $tmp_tool_file
    if [ $? -eq 0 ]; then
       echo "Updated $pkg"
@@ -172,14 +180,19 @@ for pkg in $pkgs; do
    fi
 done
 
-if [ $pkgs_updated -ne 0 ]; then
-   cp $tmp_tool_file $tool_file
+if [ $pkgs_updated -gt 0 ]; then
+   update_tool_header $tmp_tool_file
    if [ $? -ne 0 ]; then
-      warn "Failed to copy $tmp_tool_file to $tool_file"
-   else
-      rm $tmp_tool_file > /dev/null
-      exit_status=$((exit_status | $?))
+      warn "Failed to update tool header"
+   else 
+      cp $tmp_tool_file $tool_file
+      if [ $? -ne 0 ]; then
+         warn "Failed to copy $tmp_tool_file to $tool_file"
+      else
+         rm $tmp_tool_file > /dev/null
+         EXIT_STATUS=$((EXIT_STATUS | $?))
+      fi
    fi
 fi
 
-exit $exit_status
+exit $EXIT_STATUS