Download the Arduino IDE
ARDUINO 1.8.9
The open-source Arduino Software (IDE) makes it easy to write code and upload it to the board. It runs on Windows, Mac OS X, and Linux. The environment is written in Java and based on Processing and other open-source software.
This software can be used with any Arduino board.
Refer to the Getting Started page for Installation instructions.
HOURLY BUILDS

Download a preview of the incoming release with the most updated features and bugfixes.
Windows
Mac OS X (Mac OSX Mountain Lion or later)
Linux 32 bit , Linux 64 bit , Linux ARM, Linux ARM64

LAST UPDATE
14 April 2015, 08:41:16 CET
BETA BUILDS

Download the Beta Version of the Arduino IDE with experimental features. This version should NOT be used in production.

Windows
Mac OX (Mac OSX Mountain Lion or later)
Linux 32 bit, Linux 64 bit, Linux ARM, Linux ARM64

BETA
Previous Releases

Download the previous version of the current release the classic Arduino 1.0.x, or the Arduino 1.5.x Beta version.

All the Arduino 00xx versions are also available for download. The Arduino IDE can be used on Windows, Linux (both 32 and 64 bits), and Mac OS X.

Source Code

Active development of the Arduino software is hosted by GitHub. See the instructions for building the code.

The source code archives of the latest release are available here. The archives are PGP-signed so they can be verified using this gpg key.

Other Software
Easy Installation Procedure (recommended): Download the Upgrade Image then please follow the steps in the Yún sysupgrade tutorial.
Advanced Installation Procedure: This procedure is only recommended to advanced users who wish to completely re-flash the Yún including its U-Boot bootloader. These instructions on reflashing the base images are for reference only. Following them will void your Yún's warranty.

Packages List
The list of available packages for the Yún is available here.
See the list of changes.
Terms of Use

By downloading the software from this page, you agree to the specified terms.

THE ARDUINO SOFTWARE IS PROVIDED TO YOU "AS IS" AND WE MAKE NO EXPRESS OR IMPLIED WARRANTIES WHATSOEVER WITH RESPECT TO ITS FUNCTIONALITY, OPERABILITY, OR USE, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR INFRINGEMENT. WE EXPRESSLY DISCLAIM ANY LIABILITY WHATSOEVER FOR ANY DIRECT, INDIRECT, CONSEQUENTIAL, INCIDENTAL OR SPECIAL DAMAGES, INCLUDING, WITHOUT LIMITATION, LOST REVENUES, LOST PROFITS, LOSSES RESULTING FROM BUSINESS INTERRUPTION OR LOSS OF DATA, REGARDLESS OF THE FORM OF ACTION OR LEGAL THEORY UNDER WHICH THE LIABILITY MAY BE ASSERTED, EVEN IF ADVISED OF THE POSSIBILITY OR LIKELIHOOD OF SUCH DAMAGES.