This guide covers installation of ContikiOS 2.7. There are basically three way of installing ContikiOS:
- Download Instant Contiki 
- Download ContikiOS from Sourceforge repository 
- Clone ContikiOS from Github repository 
Using Instant Contiki
This is the easiest way of installing and using ContikiOS. You simply need to download Instant Contiki, which is a virtual machine created with all necessary toolchains and software for ContikiOS development.
Link to download Instant Contiki: 
After downloading Instant Contiki you need also to download either VMWare Player or VirtualBox, if you are using Windows as your host OS. If you use MacOS X you should download VMWare Fusion, instead of VMWare Player.
IMPORTANT: To login in to Instant Contiki: username: user passwork: user
Using Sourceforge repository
This method requires an existing installation of a Linux-based operating system. The guide assumes you are using Ubuntu 12.04 but should still be useful for similar versions.
Download contiki-2.7.zip from http://downloads.sourceforge.net/project/contiki/Contiki/Contiki%202.7/contiki-2.7.zip
Unzip the file. For the purposes of this guide, it is assumed that the file is unzipped into /home/user/
Rename the folder from contiki-2.7 to contiki.
mv contiki-2.7 contiki
Install all the required packages for compiling and running ContikiOS.
If you are using a MSP430-based platform (such as Tmote) you only need the following packages: binutils-msp430, gcc-msp430, msp430-libc, msp430mcu and mspdebug. If you intend to code for multiple platforms, you should also install the following tool chains for other micro-controller: binutils-avr, gcc-avr, gdb-avr, avr-libc and avrdude.
You can run the following command to install all packages for multiple platforms:
sudo apt-get install build-essential binutils-msp430 gcc-msp430 msp430-libc msp430mcu mspdebug binutils-avr gcc-avr gdb-avr avr-libc avrdude openjdk-7-jdk openjdk-7-jre ant libncurses5-dev
You are done! You can now try to compile and run any example, such as Hello World.
Using Github repository
This method also requires an existing installation of a Linux-based operating system. It is very similar to the previous one, but instead of downloading the source code you are going to clone it from the official Github repository.
This method eases the update of your ContikiOS to the new releases.
You need to clone the repository using the following command:
git clone git://github.com/contiki-os/contiki.git contiki
After that you need to download all development tools as described in the previous installation method.
Primary contributors: Pedro, Kwame