Command ls causes logout

[Bogdan Bivolaru]

Using luii's proposed template from #405:

1. Operating System: Manjaro Linux (Arch Linux based)
   

   Node version (installed locally): v10.2.0 -- Would NodeOS work under nvm?
   NPM version (installed locally): 6.1.0 -- perhaps nvm could also help me from downgrading NPM
   NodeOS version (downloaded): NodeOS@1.0.0-RC3 (latest, fresh git checkout)
   Platform (either qemu, docker, raspi, etc...): QEmu, built via npm run build

2. Screenshots: https://i.imgur.com/p34GP3L.png ![screenshot_20180601_204814_ls_causes_logout](https://user-images.githubusercontent.com/104334/40856527-e4e21d7c-65e0-11e8-9ec3-373cb979c921.png)
   

3. How to reproduce:
   

3.1 npm run build
3.2 npm run start
3.3 wait for NodeOS shell
3.4 login with nodeos / nodeos
3.5 commands that work: env, echo, pwd, man, npm search
3.6 type ls -> events.js:160 -> Unhandled 'error' event
4. describing the bug: ls causes and error which is not handled, causes logout
Error is 'TypeError: Invalid non-string/buffer chunk' /bin/getty exited with code 7

OCR'ed from the screenshot linked above (and corrected manually):

> ls 
events.js:160 
  throw er: // Unhandled 'error' event 
  ^
  
TypeError: Invalid non-string/buffer chunk 
at chunkInvalid (_stream_readable.js:393:10) 
at readableAddChunk (_stream_readable.js:148:12) 
at WriteStream.Readable.push (_stream_readable.js:134:10) 
at emitOne (euents.js:96:13) at Domain.emit (euents.js:188:7) 
at Domain._errorHandler (domain.js:97:23) 
at process._fatalException (bootstrap_node.js:293:33) 
at Domain._errorHandler (domain.js:124:26) 
at process._fatalException (bootstrap_node.js:293:33) 
bin/getty /bin/logon: "/bin/getty" exited with code 7 Welcome to NodeOS!: username:

[Philipp Czarnetzki]

Duplicate #397 for now use the /bin/ls instead