How to use a guest OS installed on Windows 7 – VirtualBox to another VirtualBox – Ubuntu

If you bumped into this post somehow, that means you really really want to use a guest operating system installed on your host operating system (i.e. Windows 7) using VirtualBox to another installed VirtualBox on different host operating system (i.e Ubuntu).

The process involves the following steps:

  1. Run VirtualBox in windows 7
  2. Select File Menu, and click Export Appliances
  3. Choose your desired guest operating system that you want to use.
  4. click next to create a ovf  (Open Virtualization Format) of your guest os.
  5. Now, copy your guestos.ovf file to Ubuntu and run VirtualBox.
  6. Select File Menu, and click Import Appliances
  7. Select guestos.ovf file and click next.
  8. Boom ! You got it !

Cheers !

Install VirtualBox in Ubuntu 12.04

September 10, 2012 1 comment

Installing VirtualBox in Ubuntu 12.04 is very easy, and what you need to do is to run the following commands in your terminal.

Open your terminal, login as  root, and run the command below to update your system:

apt-get update

After that, run the following commands to add VirtualBox repository’s key and VirtualBox repository in Ubuntu:

wget -q -O- | sudo apt-key add –
sh -c ‘echo “deb precise contrib” >> /etc/apt/sources.list’

Now, you are ready to install VirtualBox in your system using the following command:

apt-get install virtualbox-4.1

Enjoy your installed VirtualBox to load and run Guest Operating System  in it’s own virtual environment.

Trip-to-Kaptai – We danced, we sang, and we explored together

Writing down my favorite things has always been difficult for me. If you ask me, what is your favorite movie? I wouldn’t be able to point out that is truly my favorite. I have traveled a lot in my life, both in Asia and Europe. Not surprisingly, I wouldn’t be able to identify one trip that I could consider as the best one in my life. Despite the fact that I am bad at pinning down my favorite things, I finally dare to write up something about Study-Tour-to-Kaptai.

 I was not especially excited about this study tour. I chose to attend this tour because I believe, being there would give me an opportunity to explore Kaptai in a different way with my colleagues and students. Also, it would allow me to get a chance to know each other very well.

On Friday, January 14, at 12:00 am, finally the blissful journey began with the introductory speech from our eminent Akhter Sir.

Listen to me ladies and gentlemen – we are ready to leave

The Train

The ecstasy began when the train started to leave everything behind with its monotonous poo-jhik-jhik sound. I along with other faculties were listening to students cacophony while standing in front of their compartment. The song that gained my attraction was “Why this Kolaveri di” (sung by some of my students) which in fact forced me to believe that this song is worthy to listen. Thanks to those singers who made the journey melodious by singing the so-called flop song of the year.

Riaz sir, with a strange look, “does this song really exist?”

The Game

Very few people in this crazy world get a chance to teach their boss/seniors. Surprisingly, I am the lucky one. Correct, you just read my mind.  I got a chance to teach 29 (card game) to our Akhter sir. Guess what, he grabbed it pretty quickly and became one of my finest students by beating our opponent for three consecutive rounds. And, the game continued…

Midnight Round

No, seriously, it’s a midnight round not mid-noon.  We were going to pay a courtesy visit to our students.  The effrontery of Mousum was the most interesting part. His aberrant attitude duped most of the teachers and students to pay money.

Mousum at his best.

A tour without dance and songs wouldn’t be considered as a complete tour. Not surprisingly, Akhter sir took the initiative and changed the ambience by forcing students to dance with us. As a result we came to see some good dancers – Adib, Faysal, Adhity and Sajib. Albeit I wanted to dance, but I couldn’t dare because of their “Chammak Challo” type songs (doesn’t go with my image).

Faysal and Adib dancing – Chammak Challo 🙂

Scenic Drives

The next day, after having our breakfast from the renowned Hotel Zaman of Chittagong, the scenic drive to Kaptai started. I would recommend you to go for a drive there – at least once in your lifetime to see the real green Bangladesh. Special thanks to Anondo Sir (KB) for showing us the Karnafuly Paper Mills where the papers get produced. It was so much fun to see the papers producing, which I had read in my childhood. After that, the scenic drives continued till we reached the next spot (Zoom Restaurant). A recommendation again, you should spend your entire day there because after visiting the place, just one word came from my mind, that is “Masallah”.

Zoom Restaurant and Karnafuly Paper Mills

Picnic Spot

Finally, the most awaited picnic spot has come, and we paid a courtesy visit to the regional Navy Headquarter. Visit to the Navy headquarter was special to me, because they showed us the natural beauty of Kaptai by their boat, which in fact fulfilled one of my dreams – a journey by bus, train and boat altogether at the same day.

Picnic Spot

The cultural show began and we saw some tremendous performances from our students. The part that I would remember for my entire life, was Sayef’s pathetic attempt of mind reading of teachers (specially my one). A fantastic poem from our lovely poet KB sir cheered us for the next event. The picnic ended with a DJ from one and only DJ FISA.

The next day, I woke up very early again. We were waiting for the train to stop at Kamlapur. As you can imagine, I was really tired—but I had to go to office for work!

Study tour to Kaptai was truly a special one for me — not because of the places or even because of the journey, but because of the precious time I spent with my wonderful colleagues and students.

Thanks for reading !!

Lyrics of Baka Nodi/Paban Das — বাঁকা নদী/পবন দাস

Special Thanks to Ferdous Alam (my friend) for this lyrics. যদি কেও কোন ভুল থাকে, তবে অবশ্যই জানাবেন ।।

♪♪ বাঁকা নদী/পবন দাস

এক ব্যাটা মাথা কাটা
বল্‌ শালা মালসা চাটা
কামাই নাই রাস্তা হাঁটা
দাদুর খাটা ভাদর দড়’এ

এক ব্যাটা মাথা কাটা
বল শালা মালসা চাটা
কামাই নাই রাস্তা ঘাটা
দাদুর ঘাঁটা ভাদর দড়’এ

তার বিল গাবানো স্বভাব বটে
তার বিল গাবানো স্বভাব বটে
ঢিল পেয়ে ডুব মারে ঘাটে
তার বিল গাবানো স্বভাব বটে
ঢিল পেয়ে ডুব মারে ঘাটে
নীল করে সে ষাঁড়ের পিঠে
কিল মারে বাবা শিবের ঘাড়ে

কি মজা দেখলাম রে
এসে এই বাঁকা নদীর ধারে(২)

আর এক কথা সুধাই যখন
মেয়ে দীর্ঘ নিঃশ্বাস ছাড়ে তখন
আর এক কথা সুধাই যখন
মেয়ে দীর্ঘ নিঃশ্বাস দীর্ঘ নিঃশ্বাস ছাড়ে তখন
নদীর জল শুখায় তখন(২)
ঢুকায় রাখে পুত আমারে

কি মজা দেখলাম রে
এসে এই বাঁকা নদীর ধারে(২)

জলে’তে জ্বলছে আগুন
তার রা তে দগ্ধ বেগুন
আকাশে উড়ছে সুদূর
ময়না নামে কো ভাগাড়ে
হরিনারায়ণ তলিয়ে গেল(২)
গলিয়ে মাথা বেড়িয়ে এলো
এলো সে এলোমেলো বাঁকা নদীর মাঝবা খানে

কি মজা কি মজা দেখলাম রে
এসে এই বাঁকা নদীর ধারে
কি মজা দেখলাম রে
এসে এই বাঁকা নদীর ধারে
কি মজা দেখলাম রে
এসে এই এসে এই এসে এই বাঁকা নদীর ধারে
এসে এই এসে এই বাঁকা নদীর ধারে।

How to reset root/single_user password in Ubuntu on a Virtual Machine

November 10, 2011 3 comments

In order to access the grub menu on a virtual machine, you need to hold the shift key down for a while. You must let your virtual machine to capture your mouse before holding the shift key. Follow the steps to change your password:

1. Let your virtual Machine to capture your mouse.
2. Hold the shift key down to get the grub menu.
3. Select the recovery mode option.
4. Select drop to root shell prompt.
5. Now, change with # passwd [username] (You can also see the list of users using # nano /etc/passwd).

Categories: Uncategorized

How to span table/figure in two columns for writing paper in latex

While writing paper in latex in two columns, you might need to span table or figure in two columns. If you follow the template and use the following, then you might not get expected result.

\begin {table} …. \end {table}


\begin {figure} …. \end {figure}

To solve this problem, just use \begin{table*}   instead of  \begin {table} and \begin {figure*} instead of \begin {figure}.  And, you will find your expected result 🙂

Converting a Visio Image to EPS

I fought for two days to understand the way of embedding eps image in latex. You cannot convert an image directly to eps from VISIO. At first, you need to convert it to PS (Post Script format). To do that you need to add a printer which can print a visio document to ps. To do it in windows 7, go to devices and printer and select add printer.

After that, Open Microsoft Visio and click print and the following window will pop up and select the printer and don’t forget to print on file and save the file as

After that you need a software that will convert the ps file to eps and you can do it with GSview. I faced the bounding box problem while converting the file to eps. To do that when you convert to eps, follow don’t forget to check it automatic bounding box calculation.

So, now you have your eps file ready to be embedded. If you still face problem with the bounding box, then you can manually edit the bounding box by opening the file using textpad or winedit. You need to change the bounding box parameter (To do that take the mouse cursor to the top left most corner of the image to see the co-ordination (normally in pt (i.e 200,300 pt) and bottom right most corner of your image and change it accordingly).

If you want to use pdflatex then you will encounter an error saying that “EPS file not supported”. To do so, you need to add epstopdf package which will convert the eps to pdf on the fly.


But, using this package might not solve your problem. You can convert according to the following sequence to avoid the bounding box problem:

Tex>Dvi, and then Dvi>pdf


Reducing paragraph gap between items in latex

In order to remove the paragraph gap between two bullets or items in latex put the following in your document class.  First one removes gap between the numbered item and second one removes gap between the unnumbered items.

%%%%%       unnumbered item       %%%%%






%%%%%          for unnumbered item       %%%%%






You can define your items using the following way:





Some useful tips for Latex

To remove the hyphenation from the line break use the following in your document class:



To add urls in your document use the url package and include this in your document to use it:


And use  the following command to add URLs:

\url { your url}

Referring to a section, figure, subsection or table you can use  the following commands:

~\ref{your referring label}

And to refer a listing label use only \ref instead of ~\ref.

To generate a quotation in latex use this “ for left quote and use this for right quote.

For special character å use \r{a}, for ä use \”{a} and for ö use \”{o}.

Listing in Latex

In order to include code, algorithm, pseudo-code listing is very useful package. To include listing package, include this in your document class.


The following tag shows how you can place your code or algorithm in latex .

\begin{lstlisting}[float = h, caption= Title, label=label, belowcaptionskip=0.4cm]

Place your code or algorithm here.


You can even include your source code directly to your documents. For example:


To add the “List of Listings” in your documents use the following in your main.tex file.


I have got a style for listing somewhere from the internet as shown in  figure below:

To use the style add this in your document class:




basicstyle=\footnotesize\ttfamily, % Standardschrift

%numbers=left,               % Ort der Zeilennummern

numberstyle=\tiny,          % Stil der Zeilennummern

%stepnumber=2,               % Abstand zwischen den Zeilennummern

numbersep=5pt,              % Abstand der Nummern zum Text

tabsize=2,                  % Groesse von Tabs

extendedchars=true,         %

breaklines=true,            % Zeilen werden Umgebrochen



%        keywordstyle=[1]\textbf,    % Stil der Keywords

%        keywordstyle=[2]\textbf,    %

%        keywordstyle=[3]\textbf,    %

%        keywordstyle=[4]\textbf,   \sqrt{\sqrt{}} %

stringstyle=\color{white}\ttfamily, % Farbe der String

showspaces=false,           % Leerzeichen anzeigen ?

showtabs=false,             % Tabs anzeigen ?






showstringspaces=false      % Leerzeichen in Strings anzeigen ?