I'm opening this issue because:

• npm is crashing.

What's going wrong?

Apparently, the 6.0.0 version of npm is incompatible with NodeJS under 6.0.0 and crashes with the following stacktrace:

/home/xxx/.envirius/envs/node-5.9.1/lib/node_modules/npm/bin/npm-cli.js:79
      let notifier = require('update-notifier')({pkg})
      ^^^

SyntaxError: Block-scoped declarations (let, const, function, class) not yet supported outside strict mode
    at exports.runInThisContext (vm.js:53:16)
    at Module._compile (module.js:387:25)
    at Object.Module._extensions..js (module.js:422:10)
    at Module.load (module.js:357:32)
    at Function.Module._load (module.js:314:12)
    at Function.Module.runMain (module.js:447:10)
    at startup (node.js:142:18)
    at node.js:939:3

How can the CLI team reproduce the problem?

1. Install any version of NodeJS under 6.0.0 and npm at 6.0.0;
2. Attempt to execute npm -v.

Context:

OS: Linux / Archlinux
Env: envirius
NodeJS versions that are failling: 4.1.0, 4.1.1, 4.1.2, 4.2.0, 4.2.1, 4.2.2, 4.2.3, 4.2.4, 4.2.5, 4.2.6, 4.3.0, 4.3.1, 4.3.2, 4.4.0, 4.4.1, 4.4.2, 4.4.3, 4.4.4, 4.4.5, 4.4.6, 4.4.7, 4.5.0, 4.6.0, 4.6.1, 4.6.2, 4.7.0, 4.7.1, 4.7.2, 4.7.3, 4.8.0, 4.8.1, 4.8.2, 4.8.3, 4.8.4, 4.8.5, 4.8.6, 4.8.7, 4.9.0, 4.9.1, 5.0.0, 5.1.0, 5.1.1, 5.2.0, 5.3.0, 5.4.0, 5.4.1, 5.5.0, 5.6.0, 5.7.0, 5.7.1, 5.8.0, 5.9.0, 5.9.1, 5.10.0, 5.10.1, 5.11.0, 5.11.1, 5.12.0.