Run:

source ~/.profile 

再试一次

尝试以上步骤，在Ubuntu 20上无效。 对于Ubuntu 20，像上面建议的那样删除cmdtest和yarn。使用以下命令安装纱线:

curl -sL 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

Run:

source ~/.profile 

再试一次

也有此问题(windows)，修复是完全关闭所有终端实例，然后重试。

yarn包(目前是cmdtest包的别名)的名称冲突。你要找的包装是yarnpkg。所以，试试这个命令:

sudo apt-get remove cmdtest
sudo apt-get install yarnpkg

不幸的是，在yarnpkg中，命令纱被命名为yarnpkg。你可能想要创建一个别名:

sudo ln -s /usr/bin/yarnpkg /usr/local/bin/yarn

我在Ubuntu 17.04上也遇到了同样的问题。

这个解决方案对我很有效:

sudo apt remove cmdtest
sudo apt remove yarn
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-get update
sudo apt-get install yarn -y

then

yarn install

结果:

yarn install v1.3.2
warning You are using Node "6.0.0" which is not supported and may encounter bugs or unexpected behaviour. Yarn supports the following server range: "^4.8.0 || ^5.7.0 || ^6.2.2 || >=8.0.0"
info No lockfile found.
[1/4] Resolving packages...
[2/4] Fetching packages...
[3/4] Linking dependencies...
[4/4] Building fresh packages...

info Lockfile not saved, no dependencies.
Done in 0.20s.