use strict;

use Data::Dumper;

$_ = "10001 LONG RECORD\n
BEGIN RECORD A, CODE B, TABLE C END \n
NEXT\n
STANDARD DATA 1 BEGIN CODE A, RECORD B END NEXT\n
SHORT RECORD BEGIN TABLE B END NEXT\n
STANDARD DATA 2 BEGIN CODE C, RECORD D, FILE END;";

my(@records) = m< \bBEGIN\b \s+ (.*?) \s+ \bEND\b >gx;

print Dumper(\@records);

__output__

$VAR1 = [
          'RECORD A, CODE B, TABLE C',
          'CODE A, RECORD B',
          'TABLE B',
          'CODE C, RECORD D, FILE'
        ];