my $headerStr = pack $hdrTemplate
   , $fld1
   , $fld2
   , $fld3
   , $fld4
   , $fld5
   , $fld6
   , $fld7
   , $fld8
   , $fld9
   , $fld10
   , $fld11
   , $fld12
   , $fld13
   , $fld14
   , $fld15
   , $detailsLinesWritten
   , $detailsLineCt;
print $headerFH qq{$headerStr\n};