Tips

How Install Ubuntu inside Windows

Ubuntu is an easy to use and free operating system (based Linux) for use on personal computers. This section presents how to install Ubuntu inside Windows. For installing Ubuntu the following softwares are needed:

After installing and running the VirtualBox, you can create a new virtual machine(VM), as shown below:

In the next step, you need to assign the Ubuntu ISO file (which you download before ) to the VM. Select button, as shown below:

Now, the installation process can be started by click on the start button, as shown below:

Enjoy the Ubuntu OS inside your Windows :)

Ways to install a software in Ubuntu

APT protocol, or apturl, from a web browser: apturl works by default with Firefox. By clicking on a special link on a web page, the apturl protocol will launch the package manager to propose the installation of the package.
Via a graphical method: Ubuntu Software Center is a simple graphical way of installing and removing applications
Synaptic is a graphical front-end to apt-get command. Since Synaptic is no installed by default, it should be installed as shown follow:
sudo apt-get install synaptic
Text based methods that require familiarity with the terminal. The apt-get program is a command-line package manager, which is easy to operate and in some cases is quicker to use and more powerful than the graphical tools.
sudo apt-get install <package_name >
GDebi is a simple graphical tool to install .deb files. It automatically checks packages for their dependencies and will try to download them from the Ubuntu software repositories if possible. To install GDebi, open a Terminal and type:
sudo apt-get install gdebi
dpkg is a command-line tool used to install .deb files. To install a package with dpkg, open a Terminal and type the following:
cd directory
sudo dpkg -i package_name.deb

Shell scripting in Ubuntu

A shell script contains a list of command lines which are written for the shell (in Unix, a shell is a command interpreter). Shell reads the commands from keyboard (shell terminal) or from file (shell script) and uses the system kernel to execute them.

There are two different shell syntax: Bourne shell and C shell. Each script in Unix begins with two characters (#!). For Bourne shell script the rest of the line will be /bin/sh.

#!/bin/sh

Variables do not need to be declared before using them. A variable is declared as below:

Name=Amir

To access the value of the variable later:

$Name

By default, variables in sh are local and for changing a local variable to an environment variable we can use export :

export Name

Special characters inside single quotation marks will be treated literally. But in double quotation special characters (such as $) are interpreted except backslash is used to escape a special character:

S = 'Hi $Name'
echo $S

The output is: Hi $Name
But in double quotation we have:

S = "Hi $Name"
echo $S

The output is: Hi Amir
If we use backslash before special character we will have:

S = "Hi \$Name"
echo $S

The output is: Hi $Name

For accessing to the arguments of script we use 1$ for first argument, 2$ for the second argument and ...

echo "First argument is $1"

                            echo "Second argument is $2"

0$ contains name of current script:

echo "Name of script is $0"

Number of arguments of script can be retrieved as:

echo "Number of arguments is $#"

String format of all arguments of script is:

echo "String format of all arguments is= $*"

If statement general format:

                            if [ condition1 ]; then 

                                    command1 

                                    command2 

                            elif condition2 ; then 

                                    command3 

                                    command4 

                            else 

                                    command5 

                                    command6 

                            fi

Following example shows how if statement is used:

                            if [ $# = 1 ]; then 

                                    echo "Number of parameters is one" 

                            elif [ $# = 2 ]; then 

                                    echo "Number of parameters is two" 

                            else 

                                    echo "Number of parameters is more than two" 

                            fi

Note spaces before and after = are required.

While statement general format:

                            while condition ; do 

                                    command1 

                                    command2 

                            done

Following example shows how while statement is used:

                            count=5 

                            while [ $count -gt 0 ];do 

                                    echo $count 

                                    count=$(($count-1)) 

                            done

Note: Spaces before and after assign (=) is not allowed.

Linux commands

grep 'word' filename : search in the given file and returns lines which contain the word.
vertical bar (|) : connect the output of one command to the input of another command.

Permission format (Octal numbers) for a file:

rwx(owner)rwx(group)rwx(other users)
                            r:read
w:write
x:execute
  
                        

For seeing the permission of a file:

ls -l file_name

For changing the permission of a file in Octal format:

                            chmod 750 myfile

                            In this example:

                            owner has rwx (7)
group has r_x (5)
other users have none (0)

For changing the permission of a file in Symbolic format:

                            chmod [references] [operator] [modes] myfile

                            Which references can be:
                            u:user
g:group
o:others
a:all

                            And operators can be:
                            + (adds)
- (removes_
= (exact)

                            And finally, modes can be:
                            r:read
w:write
x:execute

                        

For example to give permission for executing a script to all users:

chmod a+x filename

Installing Erlang on the Ubuntu

Following packages need to be installed:

sudo apt-get install fop
sudo apt-get install m4
sudo apt-get install libncurses5-dev
sudo apt-get install openjdk-6-jdk
sudo apt-get install unixodbc-dev
sudo apt-get install g++
sudo apt-get install libssl-dev
sudo apt-get install xsltproc
sudo apt-get install perl
sudo apt-get install libwxbase2.8
sudo apt-get install libwxgtk2.8-dev
sudo apt-get install libgtk2.0-dev
sudo apt-get install libqt4-opengl-dev

After installing the prerequisite packages, run the following command from the terminal:

Download Erlang/OTP:
wget http://erlang.org/download/otp_src_R15B.tar.gz
Unpack the downloaded file:
gunzip -c otp_src_R15B.tar.gz | tar xf -
or

tar zxvf otp_src_R15B.tar.gz
Move into the base directory:
cd otp_src_R15B
Set the environment variable (ERL_TOP) to find the absolute path of the installation:
ERL_TOP="`pwd`"
Set the Erlang/OTP system in the $PATH:
PATH="$ERL_TOP/bin:$PATH"

Note: Since in Unix the current directory is not in $PATH, for running a command, the shell looks up a list of directories as specified by the PATH variable. To run a command in the current directory without using $PATH, we need to call it as shown below:

./commandName

For changing the $PATH variable permanently in Ubuntu you can add the new path to the /etc/environment file as shown below:

gksudo gedit /etc/environment

Set the LANG variable:
LANG=C; export LANG
Configure the build:
./configure

If you want to install Erlang in a specific path, you can use prefix as shown below:
./configure --prefix=~/erlang
Build the Erlang/OTP package:
make
Install the Erlang/OTP package:
sudo make install
Run Erlang:
erl
Exit from Erlang shell:
q().

How install Riak

Since Riak is written in Erlang, so Erlang needs to be installed first.

Git command is also needed to be installed:

sudo apt-get install git-core

Now you can install Riak by following the below steps:

wget http://downloads.basho.com/riak/riak-1.1.1/riak-1.1.1.tar.gz
tar zxvf riak-1.1.1.tar.gz
cd riak-1.1.1
make rel

For running the Riak:

cd rel/riak/bin
./riak start
To test the installed Riak:
./riak ping
You should get "PONG" as a response

For joining the nodes to make a cluster, you need to update the IP address of each node in app.config and vm.args files.

These two files are placed at /rel/riak/etc

How to change the current user account in Linux

The su (short for substitute user) command makes it possible to change the current user without need to log out of the current session.

su myusername

Install R from source code

wget http://www.stats.bris.ac.uk/R/src/base/R-3/R-3.0.1.tar.gz
tar -xf R-3.0.1.tar.gz
./configure --prefix=/home/ag275/R
make
make install