Usage: mlr gap [options]
Emits an empty record every n records, or when certain values change.
One of -n or -g is required.
Options:
-g {a,b,c} Print a gap whenever values of these fields (e.g. a,b,c) changes.
-n {n}     Print a gap every n records. Ignored if -g is present.
-h|--help  Show this message.
