LUG meeting report, 18 September 2012

Much fun was had learning about the difference between BIOS and UEFI booting, with the help of a Fedora 17 live USB: booting a BIOS system with this gives you syslinux, but a UEFI laptop loaded GRUB with a broken set of configurations. A few internet searches told us this was a known problem, and we were able to fix the UEFI booting.

We also spent some time diagnosing CUPS and wireless driver problems, and discussing the implications of Google’s recent announcement that is supporting OAuth 2.0 authentication for several of its APIs.

A Brief Introduction To Regular Expressions

What is a Regular Expression?


A regular expression is a flexible way of defining patterns of text. It is a formal language which is interpreted by a regular expression engine (which might be part of an application or a programming language) that parses input text and compares it to the regular expression, and then performs operations on text that matches the regular expression.

Common uses of regular expressions include:

  • Matching text
  • Substituting text
  • Extracting text


The basic syntax of a regular expression is /pattern/flags. The main part is the text pattern description, and the flags control the behaviour of the regular expression engine.

Different regular expression engines support different features, and also slightly vary in their syntax. After a overview of general regexp syntax we will look at some common applications and languages and how they support regular expressions.

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Book review: ‘Digital Audio Essentials: A Comprehensive Guide to Creating, Recording, Editing, and Sharing Music and Other Audio’

Book cover
Title: Digital Audio Essentials: A Comprehensive Guide to Creating, Recording, Editing, and Sharing Music and Other Audio
Author: Bruce Fries, Marty Fries
Price: £24.95
Publisher: O’Reilly
Published: May 2005
Reviewed by: Dougie Nisbet
Review date: October 2006
Rating: 4/5


This book presents itself an interesting challenge in that it attempts to present a comprehensive guide to digital audio in a book that isn’t the size of a brick. The authors do this successfully and the book is a worthwhile read. Continue reading

Book review: ‘802.11 Wireless Networks: The Definitive Guide (Second Edition)’

Book cover
Title: 802.11 Wireless Networks: The Definitive Guide (Second Edition)
Author: Matthew S. Gast
Price: £31.95
Publisher: O’Reilly
Published: April 2005
Reviewed by: Martin Ward
Review Date: December 2005
Rating: 5/5

Calling your book “The Definitive Guide” sets the bar high at the start, and Gast does well to live up to his title and provide virtually everything you need to know about 802.11 networking.

If you are a wardriver looking for plans to make antennae out of Pringles cans, then you won’t find them here (but they are readily available on the Internet!) If you need to set up a wireless network of any size, or are just curious about how they actually work, then this is the book for you. Continue reading

Net booting a diskless Sun3 from a Linux server

My system consists of a Linux server (basically Slackware-3.6 but with kernel 2.2.10 and various other irrelevant package upgrades) and 2 Sun3’s, only one of which is ever in use at any given time (thus they use the same swap partition on the server – later).

The Sun3’s are diskless and hence boot from the Linux box, and mount all filesystems from it. The Sun’s run NetBSD 1.3.2 largely because the Sun 3 port of Linux was not very stable or mature when I set things up.
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Linux firewalls

Linux Firewalls

What is a firewall?

  • A firewall is a controlled gateway between one network and another (i.e. an intranet and the internet).
  • It is not a universal panacea for computer security. You must follow other good security practices.

Why Firewalls?

  • You cannot trust everyone. Some people take pleasure in hacking into machines. Not all are malicious but some are!
  • Your computer holds private/confidential data an you have a duty to protect it.
  • You want to limit access from within your private network to specific external information/services (i.e. not mpeg3’s)
  • You want to monitor/record traffic for audit/security purposes. Beware of privacy laws!

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