Installing Arduino Software IDE on Linux ( Debian & Ubuntu)

Linux distributions like as Ubuntu and Debian have the Arduino software available in their repositories (e.g. from the Software Center in Ubuntu). You can readily download them from there.

https://apps.ubuntu.com/ & http://packages.debian.org/stable/ or though arduino's website http://arduino.cc/en/Main/Software
Installing Arduino Software IDE on Linux ( Debian & Ubuntu)
Installing Arduino Software IDE on Linux ( Debian & Ubuntu)

Linux: Installing Arduino IDE

New Arduino Installation

If its a fresh install, then you will need to make sure that the dependencies for running the software are met.
On an Ubuntu system, the only dependencies necessary, is to have the JRE (Java Run-time Environment) in & the GCC AVR compiler tools installed. As of Arduino software version 1.0.1, the GCC AVR compiler tools are included with the downloaded Arduino software, so it is no longer necessary to install the GCC AVR compiler, only the Java Runtime Environment (JRE) is needed.

The Java Runtime may already be installed on your system, but if it is not, then when you try to run the Arduino software, it will not even start. You will need to install Java, such as OpenJDK Java 7 Runtime. http://openjdk.java.net/install/‎ , install it from the Software Center.
Or If You Like to work from commands, so from a terminal window, it can be installed using the following command:
sudo apt-get install openjdk-7-jre
 
After it being installed, it is just a matter of downloading the Arduino software, extract the folder from the download and then copy it to a suitable location such in your desktop. Open the folder & double-click the arduino file to start the Arduino IDE.
Note that your user account must be added to the 'dialout' group to be able to upload sketches to the Arduino (dialout helps in serial communication, & the codes are uploaded serially in the arduino board). After adding yourself to the dialout group, you will need restart the computer.

Updating Already Installed Arduino

Just download the newest version of the software from the Arduino website & then extract it to the folder from the downloaded zipped file. To run Arduino, open the folder and double-click the arduino file. And Click Run or Execute.

Further Information on Installing Arduino Software on Linux

For more details on Arduino software installation on a Linux system as well as links to information on installing the software on distributions besides Ubuntu & Debian, see the Installing Arduino on Linux page on the official Arduino website.