Category Archives: Unix

Coming back to Ubuntu after a long break :) and the Ubuntu days :)

So I have finally decided to start using Ubuntu once again. Its been 7 months since I stopped using Ubuntu and switched to Windows and its since I left college. One of the reasons I started using Windows was that I was developing a Java ME app then (7 months back) and had everything configured on Windows, so there were less reasons to use Ubuntu. I did upgrade my Ubuntu to 10.04, but considering that this was originally installed long ago, I wanted to format and reinstall Ubuntu, which I would be doing in a day or two.

When I booted my computer into Ubuntu- First thing I noticed were the Sticky notes all around the desktop- Few were related to my Major project- ToDos, few related to my Technical Seminar links, few were just some reminders, email addresses. There have been lot of memories associated with Ubuntu- All of my final year of engineering- I used this. Primary reason behind the switch to Ubuntu in Final year was that- I could use any of my friend’s USB sticks without worry 😛 (And I would get lot of requests for transfer of data- Mainly ebooks, assignments, movies). But then I decided to implement my Major project (Java Analyser tool using JVMTI) and there was no looking back from then on. I didn’t have any problem in connecting, configuring my Reliance Broadband+ modem and then on browsing, downloading.  I had primarily setup my Ubuntu for development and had all the IDE’s, MySQL DB, Glassfish, Tomcat App servers installed. Also I had configured Prozilla- Command line Download manager for linux after searching a lot in the Internet.

Now that I am planning to format and reinstall Ubuntu 10.10- I would have to reinstall all of these packages. I would be writing about what all applications I have installed and how to go about installing them. Also I would be using Ubuntu for my office related work.

As I am writing this, I have Ubuntu 10.10 being downloaded in the background. Looking forward to another great time with Ubuntu 🙂

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Shell script for clearing the Trash

I was facing a problem while clearing the Trash in Ubuntu. I wasn’t able to delete certaion folder and i got the message stating “Access Denied”. So i was wondering that there should be some way to do it from the command prompt using sudo and some command. I did a google for the requirement and found the following shell snippet:

rm -rf ~/.local/share/Trash/

Source: Ubuntu Forum.

Installing Java (JDK) and Setting JAVA_HOME in Ubuntu (Linux)

I know lot of you starting out new as Linux users or Java learners on Linux platform find it an issue to install JDK or may be configure it to start using after installing. At time the version of java that comes with the package manager (apt-get for Ubuntu) would be an older version and you would require you to download the compressed binaries. In any case I have outlined how to configure in both the cases.

Case: 1– You would have to download the required JDK binary package from here. And follow the Steps for Case-1 below. This would involve extracting the compressed binary and then setting up the $PATH.

Case: 2– You have installed the JDK package using the apt-get and it installs JDK to some location (I haven’t used this approach because when ever I tried I ended up with an older version of JDK, so I have not explained it in detail).

Also note that usually the Linux installation might come with the OpenJDK but I have never used that before.

Steps for Case-1

Suppose you happen to download the JDK from the Oracle Downloads site here, then you can follow the below procedure:

1. Download the required Java SE package from the Oracle Download site here.  [Download the compressed Binary and Preferably Java SE 7]

2. Extract it in to a location of you choice- I used the /home/jdk<version>

3. Update the $PATH variable to locate the jdk/bin directory so that the shell can recognize the java and javac commands. This can be done by appending the PATH variable with the location to the jdk bin. In bash you can either use a seperate alias file- .bash_aliases and refer it in the .bashrc file or directly add in the .bashrc file. Here I am using a seperate alias file: .bash_aliases – In this file u can specify the variable values- for PATH, CLASSPATH and others required ones and also aliases for you various commands.

There’s a catch here: If you just initialize the $PATH variable with the jdk bin location then you will loose out the access to other bin dirs like- /usr/bin, /bin, /usr/local/bin and so on. Instead you would have to update/append the $PATH variable.

Lets assume you extracted the JDK compressed binary to- /home/jdk1.6.0_16

(Note: the dir- jdk1.6.0_16 naming would differ based on the version of JDK you have downloaded)

So the .bash_aliases file would look something like this

[bash gutter=”false”]
JAVA_HOME=/home/usr/jdk1.6.0_16
export JAVA_HOME
PATH=$PATH:$JAVA_HOME/bin:
export PATH
CLASSPATH=$JAVA_HOME/lib/:.
export CLASSPATH
[/bash]

The ‘:‘ is the separator, for windows it would be “;“. Its optional to update the CLASSPATH as one can provide it during the execution of Java program or if you are using an IDE it will manage the CLASSPATH or for that matter if you are using an tools like Ant, Maven. So just in case you are used to providing the CLASSPATH and may be use command line at times for you demo programs here’s a small tip:

Note that in the CLASSPATH- there’s an addition value “.“. This points to the current directory and will be helpful when the class files are in the current directory. Otherwise java will search for the classes in the directories mentioned in the CLASSPATH and will return ClassNotFoundException if the current directory is not part of the CLASSPATH and the required class files are in the current directory. Other option is to use –cp and specify the classpath. In that case the value of the CLASSPATH variable is overridden with the value specified by -cp.

Steps for Case-2

Suppose you have use the apt-get command to install the JDK, the you can follow the below procedure and this has to be done every time you enter the terminal or best is to put it in a .bashrc or .bash_aliases file as mentioned above:

[bash gutter=”false”]
JAVA_HOME=/usr/lib/jvm/java
export JAVA_HOME
PATH=$PATH:$JAVA_HOME/bin
export PATH
[/bash]

Restart/Shutdown problem in Ubuntu 8.10

I spent lots of time configuring my Ubuntu 8.10 installation, installing all the required softwares. The best thing i could do was to install Prozilla- the download manager which is really awesome. Also i installed all the IDEs, RDBMS that i use. But when i tried to shutdown my system it used to hang. This used to annoy me like hell. I then googled for this problem and came across the following solution which worked for me:

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Ubuntu 8.10 Desktop Edition Available Now!!!!

UbuntuCanonical Ltd. announced the upcoming availability of Ubuntu® 8.10 Desktop Edition for free download on 30 October. In related news, Canonical also announced the simultaneous release of Ubuntu 8.10 Server Edition.

Ubuntu 8.10 Desktop Edition is designed for the pervasively connected digital lifestyle. With new 3G network support, users can move smoothly from wired and WiFi networks onto 3G cellphone networks while traveling. Ubuntu 8.10 is also built to be shared – users can start a quick “guest session” on the fly and let someone use their computer to surf the web or check email, while maintaining the security and integrity of their own data. And if that person really enjoys their brief session as an Ubuntu guest, they can put Ubuntu on any USB key and take it home to install on their own computer rather than having to burn a CD.

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Wubi- Ubuntu installer for Windows

Tired of managing partitions, bootloaders and other related issues which occur during the installation of Ubuntu??? Ubuntu 8.04 comes in with Wubi Installer which is free installer and allows you to install and uninstall Ubuntu as any other Windows application, in a simple and safe way. 

Visit here for more details: http://wubi-installer.org/

Accessing Linux Files from Windows Simplified- Ext2 installable File System

People using dual boot with Windows and Linux and have data spread across different partitions on Linux and TuxWindows will have/are faced/facing the problem of inablity to access files on Linux partitions from Windows. I was using Ubuntu 8.04 extensively some days back before facing some problems which i need to correct. And I was using Azureus for downloading movies from torrents and i found it pretty fast on Ubuntu when compared to Windows where i was using uTorrent. I was impressed by the Axxo torrents, the clarit of video and audio was just perfect and that to for a mere 699 MB. So i had some 8 movies on my Linux ext3 partition and when ever i was on Windows and thought of watching them, i had to reboot into Ubuntu and then watch them- this was really irritating. But the other day i found a blog post in Ubuntu Geek where he had listed some tools for accessing files on u’r Linux partitions from Windows. There were many and i randomly chose Ext2 Installable File System. The installation was pretty quick and there were no hassels. At the end of the installation i was prompted for drive letters for the Linux ext3 partition and the swap partition. I chose U: for ubuntu and z: for swap.

One can download the software here.

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