shithub: kwa

ref: f35a20e9357512dd66f8ff6c4c6b593b681dd276
dir: /test/p.35/

BEGIN			{ FS = OFS = "\t" }
$4 ~ /^North America$/	{ $4 = "NA" }
$4 ~ /^South America$/	{ $4 = "SA" }
			{ print }