I have events from an application containing various logger type messages, I.e: INFO, WARN, ERROR... Searching just for the string 'ERROR' returns false positives as some INFO messages contain a matching string pertaining to error detection and such... How do I match these events similar to 'grep ^ERROR '?
You could extract the log level in a field (if it isn't being done automatically). You could use the Interactive Field Extractor for this, or specify your own props/transforms. Having done so, you could search for log_level = INFO|WARN|ERROR.
For version 6.4.0 -> Settings -> Fields -> Field Extractions -> Open Field Extractor
You can also search for the events, click on the left most row expansion button, and select "Extract Fields" from the "Event Actions" menu.
This should get you started.