Firefox (64 bit)

Just a quick note for those of you wanting a 64bit version of Firefox!

You can obtain a 64bit version here! For those of you that are daring, download and install Firefox.next (version is based on a time stamp).

For those wanting something that works, you should download a version after the list of files for Firefox.next (e.g. Firefox 3.6 below).

JAVA is available (and more stable from what I can tell) in 64bit flavors and I would recommend installing a 64bit version after installing a 64 bit version of Firefox
Note that Flash is not available for 64 bit browsers yet (unless you are on linux).

Finding and Deleting Files

Today, I was trying to remove a bunch of temporary files using the DOS command prompt on Windows Vista. What a pain in the butt!

Let's assume that I have a bunch of unwanted ".tmp" files in the sub-directory "subdir". The directory "subdir" also has other sub-directories containing more files that I would like to delete.

For those of you familiar with Linux, to find and delete files its as easy as the following command:

find ./subdir/ -name '*.tmp'-exec rm -f {} \;

Unfortunately, I couldn't muster something like that up on Windows Vista. I tried stuff like

dir /B /S | find ".tmp"

This produced the full path of the files that I no longer wanted. When I then tried to pipe those files to del, like

dir /B /S | find ".tmp" | del

Vista just said 'The syntax of the command is incorrect.'

To make a long story short, I was finally able to come up with the following:

for /R %i in ("*.tmp") do del %i

Do you have an alternative way of finding and deleting files?

Windows and problem playing DVDs

The other day on a short road trip we tried playing a DVD on our laptop and got the following message:

"Windows Media Player cannot play this DVD because there is a problem with digital copy protection between your DVD drive, decoder, and video card. Try installing an updated driver for your video card."

As soon as I got an internet connection, I tried downloading a driver for my video card. After installing it, I assumed that the DVD would play (after all, the message told me it would!).

No luck. I then downloaded new firmware and drivers for my DVD drive. The message did say something about my DVD drive too ...

Again, no luck. Well, what else is there? Then I noticed the word 'decoder' in the message and decided to pursue that option.

I tried a few things, but the one that actually did the trick was to download the XP Codec Pack. After downloading and installing these codecs, I was finally able to play the DVD that we brought to occupy our time on our short road trip!

Comparing XML Documents Semantically

I have been interested in comparing the contents of XML documents for some time now.

What I wanted to do is to perform a 'Diff' on 2 XML documents and determine whether or not they are the same document (regardless of whitespace or child element ordering).

In JAVA, I came across XmlUnit. This piece of software is excellent for determining whether or not 2 separate XML documents are equal.

In Perl, I came across XML-SemanticDiff. I thought it was great until I re-ordered the elements in one of my documents. Then this module wasn't so great anymore.

Since I really needed a piece of software equivalent to XmlUnit in Perl, I decided to create my own module and to call it XML-SemanticCompare. This new module really does perform a semantic diff on XML documents:

• Child element re-ordering doesn't result in false negatives.
• Whitespace is trimmed from text by default when comparing text and attribute values [can be turned off].
• Attributes can be ignored [turned off by default].

Using the module is extremely straightforward:

  use XML::SemanticCompare;
  my $x = XML::SemanticCompare->new;

  # compare 2 different files
  my $isSame = $x->compare($control_xml, $test_xml);
  # are they the same
  print "XML matches!\n"
    if $isSame;
  print "XML files are semantically different!\n"
    unless $isSame;

  # get the diffs
  my $diffs_arrayref = $x->diff($control_xml, $test_xml);

  # test xpath statement against XML
  my $success = $x->test_xpath($xpath, $test_xml);
  print "xpath success!\n" if $success;

The only downside to this piece of software is that it isn't very efficient (although, it isn't terribly inefficient either).

If you find yourself trying to compare XML documents DOM trees for equality and you are using Perl, please check out XML-SemanticCompare. If you can make the code more robust and efficient, please do!

A perl script to rename your files

For those of you looking for a cool way to rename your files, here is a little script that could work wonders for you.

Basically, this scripts takes in a PERL substitution expression and applies it to the filename of interest.

To get started, copy the script below into a file called 'rename.pl'. Once you have done that, then read the usage instructions by running the script with the '-h' option. Of course, you will need perl installed on your machine.

So why write this script? Because I got sick and tired of manually renaming files by hand. Some people have files called 'some_file.txt'. I prefer that file to be called 'SomeFile.txt'.

To accomplish this, all I have to do is run the script like so:

   perl rename.pl -u "s/_/ /g" some_file.txt

followed by

   perl rename.pl "s/ //g" "Some File.txt"

Note: The -u option causes the first letter of each word separated by a space to be capitalized.

Okay, maybe its quicker to manually do this for a single file, but if you are on Windows and have a whole folder full of files like that, then the process is:

   for %v in (*.txt) do perl rename.pl -u "s/_/ /g" "%v" 
   for %v in (*.txt) do perl rename.pl "s/ //g" "%v"

That is all there is to it! All of the files will be renamed with 'camel' text names.

Please make sure that before you attempt to batch rename files, that you have them backed up first!

Script start [hint: dont copy this line ;-)]

#!/usr/bin/perl -w

BEGIN {
 use Getopt::Std;
 use vars qw/ $opt_h $opt_u /;
 getopt;

 # usage
        sub usage {
  print STDOUT <<'END_OF_USAGE';

  Usage: rename [-hu] sub_regex [files]

                sub_regex is any expression that you would like to
                apply to filename. You can use capturing or just 
                matching.

                -h .... shows this message ;-)
                -u .... makes first letter of each word uppercase

  examples:

                1.
         perl rename.pl "s/_/ /g" rename_me.txt
                   This renames rename_me.txt to "rename me.txt"

                2.
         perl rename.pl -u "s/_/ /g" rename_me.txt
                   This renames rename_me.txt to "Rename Me.txt"

                3. MS Windows example
         for %v in (*.mp3) do perl rename.pl -u "s/_/ /g" "%v"
                   This renames all mp3 files in the current directory such that
                   every word begins with a capital letter and all underscores
                   are replaced with spaces.


END_OF_USAGE

}
 if ($opt_h) {
                usage();
  exit(0);
 }

}

# get the substition regex
$op = shift or (usage() and exit(1));

# go through file names
chomp(@ARGV) unless @ARGV;
for (@ARGV) {
    $was = $_;
    eval $op;
    die $@ if $@;
    # cap first letter of each word
    my $newname = "";
    my @components = split(/ /, $_);

    foreach (@components) {
      my $x = $_;
      $x = ucfirst lc $x if $opt_u;

      if ($newname eq "") {

         $newname = "$x";

      } else { 

         $newname .= " $x";

      }

    }

    rename($was,$newname) unless $was eq $newname;
}

Script End [hint: dont copy this line ;-)]

Deleting shared memory segments

Recently, I found myself using IPC in a multi-threaded perl script that I wrote.

After running the script a few times I eventually ran out of memory segments and so the script would just die (turns out that the script wasn't robust enough ;-)

So after searching around, I came up with 2 commands that go through and clean, (read delete) all segments (and semaphores) on the computer. The commands need to be run from the command line.

On Solaris:

ipcs -s | awk ' $5 == "ekawas" {print $2, $5}' | awk '{ print $1}' | while read i; do ipcrm -s $i; done 

ipcs -m | awk ' $5 == "ekawas" {print $2, $5}' | awk '{ print $1}' | while read i; do ipcrm -m $i; done

On Linux/Unix:

ipcs -s | awk ' $3 == "ekawas" {print $2, $3}' | awk '{ print $1}' | while read i; do ipcrm sem $i; done

ipcs -m | awk ' $3 == "ekawas" {print $2, $3}' | awk '{ print $1}' | while read i; do ipcrm -m $i; done

Of course, you will need to change "ekawas" to a more appropriate username. To find out the username that you should be using, run 'ipcs -s' or 'ipcs -m' and see who created the segments.

Please be careful, because all segments created by all users will be listed; so don't delete ones that you didn't create!