I found krakendev's idea quite interesting.
There are two downsides:
- it will highlight all
ERRORs, even in this case:
NSLog(@"ERROR: Reason here");
- it will highlight code inside frameworks as well.
Sadly, I'm not good with bash, so I don't really know how to improve these downsides, but you might find it helpful, nonetheless. Keeping it for future reference, as well.