Depending on your GRUB setting, you might see this screen first when you boot your Linux, Press your Esc key here to go to kernel selection window.

Select the working kernel that you normally use, and press the key "e" to edit the GRUB entry for that kernel.

 You’ll come to this screen which displays the settings for the particular kernel.

 Select the kernel configuration line, and press the key ‘e‘ again.

Here you need to add init=/bin/bash at the end of the line. This is to tell your Linux system to run Bash directly, rather than executing other init scripts that normally runs during normal bootup.

 Press the "Enter" key and you’ll be brought back to this screen. Press the key "b" to boot that particular kernel.

 Your Linux system will boot straight to Bash, bypassing almost everything including the login prompt, giving you superuser access. Here you’ll probably need to remount the root filesystem in a read and write mode with the command mount -o remount,rw / as the following;

You’ll then come to the part that you’ll set the new password for your root account. At the prompt, type the command passwd, and enter your new password when requested.

And that’s just it. Reboot your Linux machine to test if it really works. You can also change password for other users here by typing the command passwd followed by the desired username, and enter the new password when requested.

Joomla is one of the most popular Content Management System (CMS) today. It is PHP based and requires no programming knowledge to add contents and do customisations of the default Joomla installation, including to change the look and feel of the pages. The following is the view of a default Joomla installation’s frontpage.

Joomla uses templates to set the display of it’s pages. With that, changing the look and feel of a Joomla page is just a matter of changing it’s templates. To view the list of installed Joomla templates, first log in to Joomla’s administration page. At the Administration panel, choose the Extensions -> Template Manager from the menu as the following;

Template Manager lists the installed template in your Joomla installation.

To change the template used by all the pages in Joomla, simply click on the radio button next to the template you desire and then click on the Default icon on the upper right of the page.

From this point forward, all the pages will use the template you have just selected.

Joomla is a PHP based Content Management System (CMS) which enables people to build websites without requiring any programming knowledge.

Joomla by default displays "Welcome to the Frontpage" as it’s default frontpage title. Some people would want to have a different frontpage title, and the following is how you can change it to any text you would want to.

The first step surely is to login to Joomla’s administration panel;

Once logged in, you’ll come to Joomla’s Control Panel as the following. At this page choose Menus -> Main Menu from the menu.

At mainmenu’s Menu Item Manager, click on Home;

Here is the place to actually change the Joomla’s frontpage title. Select Parameters (System) on the right toolbar, and edit Page Title textfield to any page title you would like to, and then click on the Save icon on the upper right of the page.

From now on the frontpage of your Joomla site will display the title you’ve previously changed.

I have a web application hosted in my local network, and it is not accessible from the internet as it is served behind a NAT. One of the way to make it accessible from the Internet is to configure reverse proxy in Apache web server at the gateway.

A reverse proxy server routes connection addressed to the internal server, and the client sees the reverse proxy server itself as the origin server.

To configure Apache to run as a reverse proxy server in SuSe, we must first make sure the required modules are loaded by Apache. The required modules are proxy and proxy_http, and the file to configure is /etc/sysconfig/apache2. Add the 2 modules among other modules in the APACHE_MODULES directive as the following example;

APACHE_MODULES="actions alias auth_basic authn_file authz_host authz_groupfile authz_default authz_user authn_dbm autoindex cgi dir env expires include log_config mime negotiation setenvif ssl suexec userdir php5 rewrite proxy proxy_http"

The second part is to configure the reverse proxy itself. Assuming the web application is located internally in http://192.168.0.10/myapp, and we would like people from the outside network to see it as http://www.domain.com/webapp, add the following lines in the /etc/apache2/default-server.conf

ProxyRequests Off

ProxyPass /webapp http://192.168.0.10/myapp
ProxyPassReverse /webapp  http://192.168.0.10/myapp

That’s all what it takes to configure the reverse proxy, and changes should take effect after the Apache web server is restarted.

The following is a reporting page for Google AdSense publishers. Other than the column "Earnings", some publishers might not know what other columns really are, and so I’ll just brief it here;

1. Page Impressions

Page impressions are the number of times a page containing Google ads are loaded or viewed. One page impression is reported per page load regardless of how many ads are there in the page. If a particular page contains 3 ads, one page impression is recorded every time the page is loaded.

2. Clicks

Clicks is the number of time visitors click on the ads appearing on your pages.

3. Page CTR

Page CTR is the number of ad clicks divided by the number of impressions for the page of ads that appears when a link unit is clicked.

4. Page eCPM

Page eCPM or effective cost-per-thousand impressions is just a reporting feature to compare revenue across different channels and advertising programs, It is calculated by dividing total earnings by the number of impressions in thousands.

PNG or Portable Network Graphics is a file format for image that employs lossless data compression. It is meant to replace patent encumbered GIF file format, hence the acronym itself is optionally recursive, which unofficially stands for PNG’s Not Gif.

Employing a lossless data compression, PNG’s images while being sharp can sometimes relatively be big in size. To keep the file size small while maintaining the sharpness of the image, there is a tool available that can further compress a PNG image, losslessly.

The command line based program is called Pngcrush, and is available for both Windows and Linux. The program can reduce the file size for up to 40% less from the original by trying various compression levels of PNG filter methods.

Running the program is as simple as supplying the input and output file, as in the following example;

$ pngcrush  input.png output.png

 | pngcrush 1.6.6
 |    Copyright (C) 1998-2002,2006-2008 Glenn Randers-Pehrson
 |    Copyright (C) 2005      Greg Roelofs
 | This is a free, open-source program.  Permission is irrevocably
 | granted to everyone to use this version of pngcrush without
 | payment of any fee.
 | Executable name is pngcrush
 | It was built with libpng version 1.2.27, and is
 | running with  libpng version 1.2.27 - April 29, 2008

 |    Copyright (C) 1998-2004,2006-2008 Glenn Randers-Pehrson,
 |    Copyright (C) 1996, 1997 Andreas Dilger,
 |    Copyright (C) 1995, Guy Eric Schalnat, Group 42 Inc.,
 | and zlib version 1.2.3.3, Copyright (C) 1998-2002 (or later),
 |    Jean-loup Gailly and Mark Adler.
 | It was compiled with gcc version 4.3.1 and gas version 2.18.50.20080610.

   Recompressing input.png
   Total length of data found in IDAT chunks    =    90188
unknown chunk handling done.
   IDAT length with method   1 (fm 0 zl 4 zs 0) =    94524
   IDAT length with method   2 (fm 1 zl 4 zs 0) =    94871
   IDAT length with method   3 (fm 5 zl 4 zs 1) =    93666
   IDAT length with method   9 (fm 5 zl 2 zs 2) =   181820
   IDAT length with method  10 (fm 5 zl 9 zs 1) =    88388
   Best pngcrush method = 10 (fm 5 zl 9 zs 1) for output.png
     (2.00% IDAT reduction)
     (2.14% filesize reduction)

   CPU time used = 0.510 seconds (decoding 0.060,
          encoding 0.450, other 0.000 seconds)

Pngcrush can also run in batch mode, where running the following command will compress all the PNG files in the current folder, and save it to a folder named compressed, adding the suffix -compr to the file name.

pngcrush -d compressed -e -compr.png *.png

A raw image file is a supposedly un-processed image file taken directly from the image sensor of a digital camera. Depending on digital camera manufacturers, a raw image file is stored using various file extensions such as NEF, CRW, SRF, DCR, and ORF.

While manufacturers normally bundle RAW image editing software along with their digital cameras, the software most likely doesn’t run in Linux. Popular third party software such as Adobe Photoshop or Apple Aperture doesn’t run in Linux as well.

This however doesn’t mean that it’s not possible at all to do the RAW image file processing in Linux, as there are alternative softwares, and they function just well.

1- Dcraw

This is a very feature rich command line based program that is actually the backend for few other GUI based RAW processing programs. While being useful for being able to be scripted for easy batch processing, there’s no way to preview the RAW image other than to see the finished products and that makes it less appealing for most users.

The following is an example on how to convert a RAW image

dcraw -n 150 -H 5 -w -q 3 -b 1.5 DSC_1704.NEF

with the followings are explanations on each of the option switches;

• -n 150 : Set the noise threshold to 150 (possible value is from 100 to 1000)
• -H 5 : Reconstruct highlights as a compromise between whites and colours
• -w : Use white balance specified by the camera
• -q 3 : Use Adaptive Homogeneity-Directed (AHD) interpolation.
• -b 1.5 : Set the brightness to 1.5
• DSC_1704.NEF : The RAW file

Running the following command will create a .ppm file which can be opened and edited by popular photo editing software such as The Gimp.

2- Ufraw

This is probably as of now the most popular RAW image editing software in Linux. Even though that it has quite a funny name (which ufraw actually stands for Unidentified Flying Raw), it’s actually a tool for serious people.

Ufraw is a very mature program for this purpose. The program provides many options for RAW image processing, and the user interface displays a lot of useful information. Ufraw however doesn’t have photo directory browser which makes it a bit hard to work on many images at once. Ufraw is available as a standalone program and as a plugin to the popular image manipulating program for Linux, the Gimp.

3- Rawstudio

Rawstudio is known to be an easy program to operate. By trying to be easy, the program lacks many options as compared to Ufraw. All is not lost however as the program itself in some ways are more desirable when compared to Ufraw.

The program comes with the default dark interface which is easier in the eyes when working with photos. It also displays thumbnails of photos in particular directory, making it easy to navigate between photos while working on multiples photos. Rawstudio also comes with split-screen mode to display two versions of the same photo side by side.

4- Rawtherapee

Rawtherapee can be considered as what we get when combining the best of what Ufraw and Rawstudio has to give.

It has a very intuitive interface, a lot of options that we can play with (more than Ufraw), directory browsing with thumbnails, and a very good workflow. I consider this as my personal favorite and would recommend it to anyone.

The only drawbacks of this program that I can think of is that though it’s a free software, it is not open source. We also need a big screen to comfortably use the program.

The easiest way to shutdown a Windows machine from Linux is by using Samba’s net command. The following command will send an RPC call to the Windows machine, telling it to shutdown;

net rpc SHUTDOWN -C "Comment here" -f -I xxx.xxx.xxx.xxx -U username%password

If successful, we’ll be presented with the following mesage;

Shutdown of remote machine succeeded

Change "Comment here" with whatever shutdown comment that you would like for the shutdown, and replace xxx.xxx.xxx.xxx with the IP address of the Windows machine that we are to shutdown. A valid username and password also need to be supplied as a parameter to the the -U switch.

For this command to be successful, the user we use must have shutdown privilege on the windows machine. The Windows machine also need to have RPC enabled, and no firewall is blocking port 135 as the port used by RPC. The net command itself however is only available if Samba is installed.

KDE 4.2 has been released, but till now it’s still not being included in Ubuntu’s main repository. This makes the Ubuntu / Kubuntu users to get stuck with KDE 4.1, probably until Jaunty Jackalope is released this April.

There are however a solution as some nice people has actually compiled the KDE 4.2 packages and creates a repository for it.

To install KDE 4.2, you’ll need to add the following line to /etc/apt/sources.list. The easiest way to to that is to run the following command from the console;

$ echo "deb http://ppa.launchpad.net/project-neon/ubuntu intrepid main" | sudo tee -a /etc/apt/sources.list

You’ll then need to add the GPG key and update your packages cache by running the following commands;

$ gpg --keyserver keyserver.ubuntu.com --recv-keys 493B3065 && gpg --export -a 493B3065 | sudo apt-key add -
$ sudo apt-get update

Your system will now update all your KDE 4 installation to the latest version when you run the following command;

$ sudo apt-get upgrade

and if you’re a Ubuntu user who doesn’t have KDE 4 installed and want to try a full KDE 4.2 experience, install the Kubuntu Desktop with the following command;

$ sudo apt-get install kubuntu-desktop

From now you’ll be able to log in to KDE 4.2 session from your GDM.