为Ubuntu 16.04安装Yarn(不确定这是否会与14.04相同，因为它与zappee对17.04的回答略有不同)

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
curl -sL https://deb.nodesource.com/setup_9.x | sudo -E bash -
apt-get update
apt-get install nodejs
apt-get install yarn

然后从你安装sylius项目的地方(/var/www/mysite)

yarn install
yarn run gulp

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

所有正确建议删除Ubuntu yarn包并通过NPM安装yarn的答案都值得称赞，下面是一个详细的答案和解释(注意，还有意见):

从yarn安装中出现No such file or directory错误的原因是您没有使用“正确的”yarn:当您使用Ubuntu软件源安装yarn时，您得到的软件是来自cmdtest黑盒测试套件的“yarn”场景测试工具。这可能不是你的意思，因为Yarn也是Javascript应用程序的流行开发生命周期工具(类似于Make、Maven等)。

Javascript Yarn工具在Ubuntu软件源中是不可用的，但是可以通过NPM安装(NPM是Yarn想要取代的另一个开发生命周期工具——所以这很尴尬…)

要让Yarn在Ubuntu中可用，首先要删除cmdtest及其工具:

$ sudo apt purge cmdtest

然后确保NPM已经安装:

$ sudo apt install npm

然后使用NPM安装Yarn:

$ npm install -g yarn

Note: using npm install -g will install a Javascript package for your current user account, which should be fine for most purposes. If you want to install Yarn for all users, you can use sudo for the NPM command, but that is not recommended: NPM packages are rarely audited for security in the context of a multi-user operating system and installing some packages might even break when installing them as "root". NPM used to warn against running it with sudo and the main reason it is not doing so today is that it annoys people that use sandboxed "root-like" environments (such as Docker) for building and deploying Javascript applications for single-user servers.

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.

也有此问题(windows)，修复是完全关闭所有终端实例，然后重试。

我在Ubuntu 18.04上也遇到了同样的问题。这对我来说很管用:

我去掉了cmdtest和纱线

sudo apt remove cmdtest

sudo apt remove yarn

使用npm全局安装yarn

sudo npm install -g yarn