It's difficult to make yarn link work as intended when developing a command line project. The easiest way is:

• yarn link in your cli project

assume your cli project is cli-project, assume the name is cliProject

# in cli-project
yarn link

• create a demo project and init with yarn

mkdir demo-project
cd demo-project
yarn init -y

• add your cli project as dependency in package.json

• yarn link cliProject in demo-project
  

# in demo-project
yarn link cliProject

now you can use yarn cliProject here. In my situation, I would

# in demo-project
yarn cliProject --version # to check if yarn link succeeded
yarn cliProject new haha-project # to test my new command