Introduction
Mbed (official website) is a collection of APIs which simplify software development for microcontrollers with ARM Cortex kernel. Mbed is maintained by ARM, in cooperation with their partners.
Mbed OS
Mbed OS is a real-time operating system that comes with the Mbed APIs.
Using MbedOS
Web IDE
The web IDE is the most convenient of getting started with the Mbed API and Mbed OS. You can generate a blank Mbed project or a project based on one of the many example projects. You can build the project on the Web IDE and download the resulting binary. You can also download the complete source package as an archive file (ZIP file) with project file stubs for the popular embedded software development environments.
Command Line Tools
Mbed CLI is a collection of command line tools for generating Mbed project stubs in the same way that the Web IDE does. With the command line tools you can create a script that generates the Mbed part of your project's source files so that these files do not need to be included in your version control repository.
To install the tools on Ubuntu Linux type
sudo apt install git mercurial sudo pip3 install mbed-cli mbed config -G GCC_ARM_PATH <toolchain path>/bin/arm-none-eabi-gcc
where toolchain path is the installation path of the GNU Arm Embedded Toolchain for Cortex M architecture.