@HeaderRecordNames   = qw/$RequestYear $RequestMonth $RequestDay $RequestSequence $RecordType $RecordSequence $Record/;
@HeaderRecordLengths = qw/A2           A2            A2          A4               A2          A2              A1486/;

...

my (@HeaderRecordNames) = unpack(@HeaderRecordLengths, $_);
my (@RecordNames[$Recordtype])=unpack(@RecordLengths[$RecordType]);