看起来我试图执行错误的yarn，因为只运行 sudo安装纱线给了我来自cmdtest的纱线。

It looks like that I was trying to execute the wrong yarn, because simply running sudo apt install yarn on my Ubuntu 18.04 gave me yarn from cmdtest.

所以我通过卸载将其解决：

So I solved by uninstalling it:

sudo apt remove yarn

并通过将其安装为官方网站进行了解释，在我的情况下（Ubuntu 18.04）是以下内容：

And by installing it as the official website explains, which in my case (Ubuntu 18.04) it was the following:

curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -

echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee
/etc/apt/sources.list.d/yarn.list

sudo apt update && sudo apt install yarn