Add the following line and change
[PATH_OF_FLUTTER_GIT_DIRECTORY] to be
the path of your clone of the Flutter git repo:

    
$ export PATH="$PATH:[PATH_OF_FLUTTER_GIT_DIRECTORY]/bin"

Run source $HOME/.<rc file>
to refresh the current window,
or open a new terminal window to
automatically source the file.

Verify that the flutter/bin directory
is now in your PATH by running:

    
$ echo $PATH
    
    Verify that the flutter command is available by running:

    
$ which flutter

which flutter dart

/path-to-flutter-sdk/bin/flutter
  /usr/local/bin/dart

which flutter dart

/path-to-flutter-sdk/bin/flutter
  /path-to-flutter-sdk/bin/dart