Monthly Archives: July 2005

Learning Perl, Fourth Edition

Learning Perl, Fourth Edition

There’s a new edition of O’Reilly’s excellent “Learning Perl”. I still have my copy of the first edition as well as at least one other edition of this book. This is the book that I first learned Perl on so it holds a special place for me and I’m excited to see the new version. The fourth edition contains new exercises and has been written with less of a *nix-bias.

You can find more information about the book on O’Reilly’s site. You can also read Chapter 11 of Learning Perl.

Intuitive is subjective

It seems like a simple statement, not incredibly groundbreaking: Intuitive is subjective. Computer users frequently ask for a “user-friendly” interface or an intuitive interface. However, these phrases, “user-friendly” and “intuitive interface” have no meaning when standing alone with no context. Each user has their own thoughts as to what exactly comprises a user-friendly interface. For example, some people might think that a graphical interface is highly intuitive, they can just point and click their way through a task. Others believe that command-line interfaces are quite intuitive and they can accomplish tasks quicker using those than if they had to use a GUI.

I’m not going to pass judgement as to which, if either, of these groups is better. I don’t think that’s for me to judge. It is, however, something that needs to be understood by those who seem to expect that when they say “user-friendly” that they mean a GUI. One should not assume that user-friendly means or has anything to do with a graphical interface.

Qmail “Although I’m listed as a best-preference mx or a for that host”

Another one that I don’t have to fix often so I’ll likely forget it.

Qmail error “Although I’m listed as a best-preference MX or a for that host, it isn’t in my controls/locals file, so I don’t treat it as local. (#5.4.6)”

It shows up in the log concatenated:

failure: Sorry._Although_I’m_listed_as_a_best-preference_MX_or_A_for_that_host,/it_isn’t_in_my_cont

Anyway, I fixed it, hopefully correctly, by placing the hostname in the /var/qmail/control/locals file and the /var/qmail/control/rcpthosts file and restarting qmail.

Linux Firewalls, Third Edition

I just realized with that previous post that I hadn’t updated anything here since May. Shame on me. I’ve been working on multiple books and projects. The next book to be released is a revision of Linux Firewalls, originally done by Robert Ziegler. I’ve updated the content and added several new chapters. Here’s the link to the book which will be published under the “Novell Press” moniker now. I’ll be updating that link shortly when Amazon has it listed.

Pop up ads from plugins as seen on Drudge Report

Mozilla Firefox has kept its users happy with advanced features such as pop-up blocking and tabs and other things that users of IE are just now thinking about getting in the next version of Internet Explorer. Even with the pop-up blocking capabilities of Firefox, some pop-ups do get through. These pop-ups are spawned from within ads or other areas of the site that use plugins such as Flash. One site that does indeed use this tactic is the Drudge Report. It’s possible to configure Firefox to stop these spurious popups too.

Here’s how to do in Windows which is what I happen to be using this afternoon:

  • Open Firefox and select about:config as the location.
  • Right click anywhere within the config window and select New->Integer
  • Within the preferences window, type privacy.popups.disable_from_plugins, see Figure 1.


    Blocking Popups with Firefox


  • Next, you’ll enter the value for this preference. In this instance, enter a 2 to block all pop-ups. A value of 0 enables these types of pop-ups which you may need to do for certain sites (designed by people who need to take a web usability class, no doubt). A value of 1 enables some types of pop-ups. Figure 2 shows the value entry dialog.


    Blocking Popups from sites such as


  • Enjoy.