2013 in review

Posted: December 31, 2013 in Uncategorized
Tags: , ,

Happy New Year to all my blog subscribers and readers!!

The WordPress.com stats helper monkeys prepared a 2013 annual report for this blog.

Here’s an excerpt:

The Louvre Museum has 8.5 million visitors per year. This blog was viewed about 130,000 times in 2013. If it were an exhibit at the Louvre Museum, it would take about 6 days for that many people to see it.

Click here to see the complete report.


Celebrating 100k+ Views

Posted: October 23, 2013 in Uncategorized
Tags: ,

Hi everyone,

Today my blog crossed over 100,000 views. This is a post to thank all my blog subscribers for their support and also to all others who follow my blog.

100,000+ Views

Once again, Thank you all! Hope you have great day. Happy Blogging! :)


This is a guide on how to install Zorin OS 7 (64-bit) in Virtual Box. Hope this helps!


  1. Zorin OS Core ISO : Download Link (~1.5GB)
  2. Virtual Box : Download Link  (~96 MB)
  3. Atleast 8 GB of free hard disk space.

Installation Procedure:

First, download and install Virtual Box in your computer using the download link mentioned above. Also, download the Zorin OS ISO to any location of your choice.

Open Virtual Box, click on “New“:


Now, enter “Name” anything as you wish, Type asLinux” and Version asUbuntu (64-bit)“. Then, click on “Next“.

Name and Operating system

Now, select the amount of RAM you want to allocate for your Zorin OS Virtual machine. I would recommend a minimum of 512MB-1024MB. I have allocated 1024 MB (i.e. 1 GB of RAM) for my Zorin OS VM.

Memory Size

We need to create a virtual hard drive. Click on “Create a virtual hard drive now” and click on “Create“.

Create Hard Drive

Now, select the option ” VDI(Virtual disk Image) ” and click on “Next”.

Hard Disk Type

Now, select “Dynamically allocated“. {NOTE: You can also go with fixed size if you want but it will take longer time to create but is faster to use }

Storage Type

Now , you can select the size of your virtual hard disk by dragging the slider across. You can also choose a custom location where you want to save your Zorin OS by clicking on the red box that I have highlighted. Make sure you allocate a minimum of 8 GB. After selecting the appropriate options, click on “Create“.


Now, Click on the Virtual machine, you created and click on “Start“.


Now, click on the small folder icon which I have highlighted in red and browse to the ZorinOS ISO file you have downloaded earlier.



Now, click on “Start” once you have selected the ISO file.


To start the installation, select the option “Start the installer directly“.


Wait a few moments for the installer to load.


Select the Language of your choice and click on “Continue“.


Click on “Continue“.


Select “Erase disk and install Zorin“.


After this step, you would be prompted to select your location. You can click on the map to select your location and click on “Continue“. Then select the keyboard layout of your choice and click on “Continue“.


Now, you can enter “Your Name” , “Your computer’s name” , “username” and a “password” of your choice and click on “Continue“.


Now, it will copy the nessasry files and install the Zorin OS.


This may take a while depending on your computer configuration.


You will get a prompt stating that the Installation is complete. Click on “Restart Now“.


Hit on the “ENTER” key when prompted.


Select the first option “Zorin” and hit “ENTER” in your keyboard.


This should boot up your installed Zorin OS.


Enter your login credentials that you created earlier during the installation phase.


You should be able to see your home screen and the Z button which is similar to the start button in Windows based systems in the lower left corner. Clicking that should bring up the menu which is very classy in my opinion and easy for newbies who are migrating from Windows to Linux.


You can open up the terminal by simply searching terminal in the search box and it should bring up the terminal.


And here is the terminal!


So Hurrayy!! You have successfully installed Zorin OS in Virtual Box !!

I just installed ZorinOS a few days back, and felt that it is a great OS especially for users who are migrating from Windows to Linux. I am still playing around with it and so far I must say it looks interesting. So go ahead, try it out and let me  know what you think. Feel free to leave a comment about it in the comments section below.

If you have any sort of queries on regarding this installation, just leave a comment below and will get back to you. Don’t forget to follow my blog to get future updates! :D


Nokia just officially announced the all new Nokia Lumia 1020 in New York. And it is simply Amaazzinng !!!

nokia lumia 1020 Picture

Phone Highlights:

  • 41MP autofocus PureView camera (with lossless Zoom)
  • 1.2 MP secondary wide-angle camera.
  • 1.5GHz dual-core Krait CPU
  • 2 GB RAM
  • 1080p video recording at 30fps
  • Windows Phone 8
  • 32 GB/64GB of Internal Storage + 7GB of free SkyDrive storage
  •  Super Sensitive Touch technology (which allows you to use the phone with gloves and nails)
  • 4.5″ Clear Black AMOLED display with Nokia’s PureMotion HD+ Corning Gorilla Glass 3
  •  6-lens ZEISS optics and optical image stabilization
  • Xenon & LED Flash.
  • Completely manual camera controls (similar to the ones in DSLR cameras).
  • Bluetooth 3.0 with NFC, Dual Band Wi-Fi 802.11 a/b/g/n , GPS , Glonass support
  • 2000mAh battery with 16 days standby13.3 hours of talk time.

The complete specifications can be found here and the hands-on here.

Be sure to check out some the Promo videos below:

So, What do you think about this phone? Are you going to buy it? Feel free to leave your thoughts in the comments section below. :)


This is a guide on configuring network in CentOS in Virtual Box with screenshots (using terminal).

So, here I have used CentOS 6.3 minimal and will be discussing on configuring the Virtual Box and CentOS for network access. If you need help installing CentOS minimal in the Virtual Box, you can find the instructions in my earlier post here.


  1. Virtual Box
  2. CentOS 6.3 or 6.4

Step 1: Configure Virtual Box Network Settings:

There are different modes or ways you can configure your Virtual box network settings.

  1. Not Attached
  2. NAT
  3. Bridged Adapter
  4. Internal Network
  5. Host-Only Adapter
  6. Generic Driver

You can find more details about the different modes here.

I will be using the Bridged Adapter mode for this guide. It is faster as it treat the VM as an individual host within the network.

Open Virtual Box and right click on  your CentOS VM, and click on “Settings“.

vbox settings

Now, go to the tab Network and change the “Attached to” field to “Bridged Adapter”. Then choose the “Name” to your network interface. For example, I have a dell wireless adapter, so I choose the Name as “Dell Wireless” from the drop down menu. And finally check the field “Cable Connected.  Finally, click on OK when you are done.

network settings

So, you have now configured the Virtual Box. Now, you can start your CentOS VM by selecting you VM and clicking on “Start”.

start vm

Step 2: Configure CentOS network settings:

You can configure your network either by using Dynamic IP addressing assigned by your DHCP server or you can manually configure your IP Address statically. You can choose either static or dynamic method and can do so by editing the file /etc/sysconfig/network-scripts/ifcfg-eth0.

Method 1: Dynamic IP 

We can configure the network by using Dynamic IP address which are assigned automatically by the DHCP server. This is the simplest way to configure your network.

NOTE: You will have a line that starts with HWADDR in the your config file, do not change or modify that line.

In your terminal, type the following:

vi /etc/sysconfig/network-scripts/ifcfg-eth0

Now, add/modify the file as follows (DO NOT CHANGE the HWADDR line your config file):






Now, save the file by pressing “ESC” and typing :wq and hit ENTER.

To view your network config file. type the following in the terminal:

cat /etc/sysconfig/network-scripts/ifcfg-eth0

dynamic ip config

Now, you will have to restart your network. You can do so by typing the following in the terminal:

                service network restart

service network restart

To view your IP address, type the following in your terminal:

                ifconfig eth0

You can see your IP Address of the interface eth0 next to the field “inet addr:” as shown below:

ifconfig eth0

Now, if you have internet access, then you can check if you are able to ping any website. And you should be able to get the reply. For example, in your terminal type:

ping extr3metech.wordpress.com

ping results

You can press CTRL+ C to stop the ping command.

So, Hurray! you have successfully setup up your network in your CentOS Virtual Box.

Method 2: Static IP

We can also assign the network information manually by assigning the IP Address, NETMASK , GATEWAY in the network interface config file.

NOTE: You will have a line that starts with HWADDR in your config file, do not change or modify that line.

Step1 : In you terminal, type:

vi  /etc/sysconfig/network-scripts/ifcfg-eth0

Now, edit/merge the file to the following









Now, press ESC and type :wq and hit ENTER to save and exit the configuration file.

To view the config file. type the following in the terminal:

cat /etc/sysconfig/network-scripts/ifcfg-eth0

view configuration

Step 2: Change Host name: 

To change host name , you have to edit the config file /etc/sysconfig/network. If you want to know to change the host name manually, you can follow the guide I have posted earlier here.

Step 3: Assign DNS Server IP

To manually assign primary and secondary DNS Server IP addresses, in your terminal type: 

vi /etc/resolv.conf

Now, edit this file to the following:



Now, press ESC and type :wq and hit ENTER to save and exit the configuration file.

Now, if you want you can make sure you have entered and saved the correct configuration(It is a good practice to double check :D ). To view your dns config file, in your terminal type:

cat  /etc/resolv.conf


Step 4: Restart network:

Finally, all you have to do is to restart your network service. To so so, type the following in the terminal:

                service network restart

service network restart

Now, you can check your Current IP configuration, by typing the following in the terminal:

ifconfig eth0

ifconfig eth0

Now, if you have internet access, then you can check if you are able to ping any website. And you should be able to get the reply. For example, In your terminal type:

ping extr3metech.wordpress.com

 ping results

You can press CTRL+ C to stop the ping command.

So, Hurray! you have successfully setup up your network manually in your CentOS Virtual Box.

Hope this guide helped you to configure network in your CentOS Virtual Machine.

If you have any queries or suggestions regarding this guide, feel free to leave a comment and will get back at you. Don’t forget to follow my blog to get future updates! :D


Kali Linux  is the all new Backtrack Linux which is used mainly for penetration testing and digital forensics purposes which is going to be released soon by Offensive Security. They haven’t announced the release date so far but said that the work is on the way to completion.

They have released a teaser video on their upcoming release. Be sure to check the teaser video below, it looks pretty daam impressive!

You can find the official post by Offensive Security team here.


This is a guide on how we can generate Stirling numbers using Python programming language.

Stirling Number S(n,k) :

A Stirling Number of the second kind, S(n, k), is the number of ways of splitting “n” items in “k” non-empty sets.

The formula used for calculating Stirling Number is:

S(n, k) = k* S(n-1, k) + S(n-1, k-1)

Example 1:

If you want to split a group of 3 items into 2 groups where {A, B, C} are the elements, and {Group 1} and {Group 2} are two groups, you can split them are follows:

{Group 1}                    {Group 2}

A, B                                    C

A                                        B, C

B                                        A, C

So, the number of ways of splitting 3 items into 2 groups = 3.

Therefore,  the Stirling number , S(3, 2) = 3

Example 2:

If you want to split a group of 5 elements into 2 groups where {A,B,C,D,E} are the items and {Group 1} and {Group 2} are two groups, it can be done in a total of 7 ways. So,

S(4, 2) = 7

This is the code that I have written to generate Stirling Numbers.

# Stirling Algorithm
# Cod3d by EXTR3ME
# http://extr3metech.wordpress.com

def stirling(n,k):
    if n<=0:
        return 1
    elif k<=0:
        return 0
    elif (n==0 and k==0):
        return -1
    elif n!=0 and n==k:
        return 1
    elif n<k:
        return 0

        return (k1*(stirling(n1-1,k1)))+stirling(n1-1,k1-1)

print   stirling(1,1)
# Output = 1

print stirling(5,2)
# Output  = 15

print stirling(5,3)
# Output  = 25

print stirling(5,4)
# Output  = 10

print stirling(5,5)
# Output  = 1

print stirling(20,15)
# Output  =  452329200

#print stirling(30,10)

# End of Code

Note: When the values of n and k are large , it will take longer to calculate. For example, I have hashed out print stirling(30, 10) , as it can take a while to calculate. You can always unhash it and test how long it takes to calculate in your computer. Feel free to leave any comments or feedback.

Hope this helps. You can always subscribe to my blog to get more updates! Happy Coding!