sudo apt-get install python-software-properties 
sudo add-apt-repository ppa:chris-lea/node.js 
sudo apt-get update 
sudo apt-get install nodejs npm

但是当我来到最后一行sudo apt-get install nodejs npm显示一个错误：

Failed to install some packages. This may mean that
You requested an impossible situation or if you are using the distribution
distribution that some required packages have not yet been created or been
been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
nodejs: Conflicts: npm
E: Failed to correct problems,you have held broken packages.

然后我卸载了ppa：chris-lea / node.js，我试图第二个选项：

sudo apt-get install node.js
sudo apt-add-repository ppa:chris-lea/node.js
sudo apt-get update
sudo apt-get install nodejs npm

同样的错误，终端说npm是在最后的版本，但也显示我的文本显示在顶部。我认为问题是ppa：chris-lea / node.js但我不知道如何解决它。