exit on EPIPE to avoid useless work

CHANGES.md

@@ -8,7 +8,8 @@ Known issues:
 
 ## bunyan 0.16.9 (not yet released)
 
-(nothing yet)
+- *Exit* on EPIPE, otherwise we sit there useless processing a huge log file
+  with, e.g.  `bunyan huge.log | head`.
 
 
 ## bunyan 0.16.8

bin/bunyan

@@ -910,6 +910,7 @@ function emit(s) {
 process.stdout.on("error", function (err) {
   if (err.code === "EPIPE") {
     // Pass. See <https://github.com/trentm/json/issues/9>.
+    drainStdoutAndExit(0);
   } else {
     warn(err);
     drainStdoutAndExit(1);