title: npm command not working on ubuntu
body: <p>I installed node and npm on Ubuntu 14.04 and when I try to use any npm command, I get the following error:</p>
  
  <pre><code>/usr/local/lib/node_modules/npm/lib/config/cmd-list.js:113
  module.exports.aliases = Object.assign({}, shorthands, affordances)
                              ^
  TypeError: Object function Object() { [native code] } has no method 'assign'
  at Object.&lt;anonymous&gt; (/usr/local/lib/node_modules/npm/lib/config/cmd-list.js:113:33)
  at Module._compile (module.js:456:26)
  at Object.Module._extensions..js (module.js:474:10)
  at Module.load (module.js:356:32)
  at Function.Module._load (module.js:312:12)
  at Module.require (module.js:364:17)
  at require (module.js:380:17)
  at /usr/local/lib/node_modules/npm/lib/npm.js:37:17
  at Object.&lt;anonymous&gt; (/usr/local/lib/node_modules/npm/lib/npm.js:471:3)
  at Module._compile (module.js:456:26)
  </code></pre>
  
  <p>I'm new to using node and I didn't find any solution to such an error online</p>