Oracle Virtualization and Cloud Consulting
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Tools for checking broken web links - part 2

Part 1 of this 2-part series on Linux link checking tools reviewed the tool linkchecker. This post concludes the series by presenting another tool, klinkstatus. Unlike linkchecker which has a command-line interface, klinkstatus is only available as a GUI tool.

Tools for checking broken web links - part 1

With a growing web site, it becomes almost impossible to manually uncover all broken links. For WordPress blogs, you can install link checking plugins to automate the process. But, these plugins are resource intensive, and some web hosting companies (e.g., WPEngine) ban them outright. Alternatively, you may use web-based link checkers, such as Google Webmaster Tools and W3C.

How to redirect sudo output to a file requiring root permission

sudo is the recommended way to execute a command which requires root permission. In effect, the target command takes on the permission of root without having to provide the root password. Consider the following scenario. In order to save the changes made to the iptables firewall rules, I need to run the following command which outputs the changes to a file with root permission. $ sudo iptables-save > /etc/iptables/rules.v4bash: /etc/iptables/rules.v4: Permission denied

Upgrade from Fedora 19 to 20 using fedup

The recommended upgrade method for Fedora is to use the fedup tool. Below is my experience in following the fedup procedure to upgrade from Fedora 19 to 20. The upgrade was done over the Internet ("network upgrade") instead of from a local DVD media.

  1. Back up all important data in the system.

How to optimize PNG images

table, th, td { border: 1px solid white; border-collapse: collapse; } th,td { padding: 15px; } My previous post introduces some tools to optimize JPEG images. The focus of this post is on optimizing PNG images. Two complimentary tools will be presented: optipng, and pngquant.

How to optimize JPEG images

table, th, td { border: 1px solid white; border-collapse: collapse; } th,td { padding: 15px; } Poor load time degrades the user's experience of a web page. For a web page containing large images, optimizing images can significantly improve the load time performance which leads to better user experience. Moreover, if a web site is hosted on a cloud service which charges for cloud storage, compressing images can be financially worthwhile.

Create video screencasts using recordmydesktop

Why make a video screen capture, aka screencast? Some possible reasons are:

  • Create a software demo.
  • Capture a video game session for playback later.
  • Keep a record of what transpires on the computer screen.

I create screencasts mainly for recordkeeping. As a result, I don't expect to edit the output video, for example, to obfuscate sensitive data, or to insert call-outs to draw attention to specific screen areas.

Building a firewall for a Debian web server

This post addresses how to configure the Linux firewall to protect a Debian-based web application server. While there are GUI tools for the job, we will focus on the command-line tool iptables. The scenario is that you have just installed Debian (or Ubuntu) on a server connected to the Internet. This will be used as a web server hosting your WordPress blog. I assume that you already have Apache, and WordPress installed.

Using double dash to specify pesky command line parameters

Many Linux commands accept command-line options and positional parameters. The grep command searches for a pattern in a given file. Its 2 positional parameters are the pattern and the filename. It accepts options such as -i which specifies that the search is case insensitive. An interesting scenario is when a positional parameter has a value starting with a dash ('-'). This makes the parameter indistinguishable from an option. For example, you try to grep the string -tea in a given file.

Tips on GNOME Classic workspaces

In the world of affordable, dual 27-inch monitors, the GNOME virtual screen feature (aka workspaces) may not hold the same prominent position as before. But, to people like myself who still operate machines equipped with only a single 19-inch monitor, using workspaces effectively is still a big productivity booster. Below are some tips for using GNOME Classic workspaces. Tip 1: Change # of default workspaces By default, the GNOME desktop has 4 workspaces available. The default number can be changed. I, for one, would like to decrease the number of workspaces to 2.

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