问题描述
试图在ubuntu 12.04上安装nodejs和npm。我用Google搜索并做到了。现在，我无法在机器上安装npm。
sudo apt-get install npm
这给了我这个
The following packages have unmet dependencies:
npm : Depends: nodejs but it is not going to be installed
Depends: nodejs-dev
Depends: node-request but it is not going to be installed
Depends: node-mkdirp but it is not going to be installed
Depends: node-minimatch but it is not going to be installed
Depends: node-semver but it is not going to be installed
Depends: node-ini but it is not going to be installed
Depends: node-graceful-fs but it is not going to be installed
Depends: node-abbrev but it is not going to be installed
Depends: node-nopt but it is not going to be installed
Depends: node-fstream but it is not going to be installed
Depends: node-rimraf but it is not going to be installed
Depends: node-tar but it is not going to be installed
Depends: node-which but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
最佳解决方法
这看起来你可能安装了chris-lea node.js ppa，这很好。但是，你没有从那个ppa安装npm，因为它破坏了debian包的工作方式。相反，只需安装nodejs即可。安装完成后，运行npm -v，您应该会看到它已安装完毕。如果您没有使用chris-lea ppa更新您在Googled的网页上的问题，以了解如何在Ubuntu上安装nodejs。
次佳解决方法
尝试安装这样的NodeJ：
sudo apt-get install nodejs
由于NodeJ安装节点和npm
第三种解决方法
我按照this documentation解决了这个问题。
要记住使用npm的指针：
mkdir ~/nodejs/ && cd ~/nodejs
sudo apt-get install npm
npm install
npm update
在开发应用程序时，如果nodejs需要任何特定模块，则运行
cd ~/nodejs
npm install modulename #for example sendgrid
有时，模块需要全局安装;然后用
sudo npm install modulename -g"
要删除模块：
cd ~/nodejs
npm uninstall modulename # if locally installed or
sudo npm uninstall modulename -g # if globally installed
npm prune有助于删除未满足的依赖项