use strict;
use warnings;

# Remove (exclude) lines beginning with "bl", "BL" or "_" and releases with a label with xx.yy.zzz.nnn(n)
while (<DATA>) {
	print unless /^(?:bl|_)|\.\d{3}\.\d{3,}$/i;
}

__DATA__
_STUDYABCD1234_1.00
_STUDYABCD1234_1.00.5678
STUDYABCD1234_1.00
STUDYABCD1234_1.00.000
p_STUDYABCD1234_1.00.000
p_STUDYABCD1234_1.00.000.5678
bl_STUDYABCD1234_1.00.000
bl_STUDYABCD1234_1.00.000.5678
BL_STUDYABCD1234_1.00.000
BL_STUDYABCD1234_1.00.000.5678