Maintaining Arduino on Ubuntu 14.04
If you want to get maintained (automatically updated) version of Arduino IDE then you install if from a package repository with its dependencies e.g. using apt-get:

sudo apt-get update
sudo apt-get install arduino arduino-core


However, this way you get a very old version (currently 1.0.5). Obviously, it is not updated too often if at all.  

If you already installed from the package repository via apt-get you can uninstall the package and its dependencies like this:

sudo apt-get remove arduino arduino-core
sudo apt-get autoremove


Better way is to download and install Arduino IDE yourself. This way Arduino software won't automatically be updated, so you should check Arduino website every now and then and download a new version if one is available. 

Open a terminal window (e.g. by pressing CTRL-ALT-T), and run uname -m to check if you are running 32 bit or 64 bit platform:

uname -m


See output:

x86_64 ==&gt; 64-bit kernel
i686   ==&gt; 32-bit kernel


Go to Arduino Download page on Download the Arduino Software and download the 32 bit or 64 bit version, depending on the Ubuntu version installed on your computer.

In a terminal window extract the package and move it to your preferred location, e.g. /opt. You need sudo rights to move it to /opt. Finally, run the install script if you want to start the IDE graphically (adds desktop icon, MIME type, default application for .ino). See the example commands below for installing the latest 32 bit version as of the time of writing to /opt.

cd ~/Downloads
tar xf arduino-1.6.7-linux32.tar.xz
sudo mv arduino-1.6.7 /opt
/opt/arduino-1.6.7/install.sh


You can also start the IDE from the terminal:

/opt/arduino-1.6.7/arduino