add error processing for stdout closing, such as on head -1

[conrado]

When piping the output through a program that might close the stdout file descriptor, such as head -1 you would be presented with an EPIPE error:

events.js:182
      throw er; // Unhandled 'error' event
      ^

Error: write EPIPE
    at exports._errnoException (util.js:1024:11)
    at WriteWrap.afterWrite [as oncomplete] (net.js:851:14)

This PR fixes that