If you don’t want to install a fixed version of the installation bundle, 
you can skip steps 1 and 2. 
Instead, get the source code from the Flutter repo
on GitHub with the following command:

    
$ git clone https://github.com/flutter/flutter.git
    

    You can also change branches or tags as needed.
For example, to get just the stable version:

    
$ git clone https://github.com/flutter/flutter.git -b stable

Add the flutter tool to your path:

    
$ export PATH="$PATH:`pwd`/flutter/bin"
    

    This command sets your PATH variable for the
current terminal window only.
To permanently add Flutter to your path, see
Update your path.

Optionally, pre-download development binaries: