$templ = 'A4 v d';;

@fields = ( 'fred', 12345, 123.456 );;

$record = pack $templ, @fields;;

print unpack $templ, $record;;
fred 12345 123.456

##</code><code>##

$templ2 = 'A4 H4 H16';;

print unpack $templ2, $record;;
fred 3930 77be9f1a2fdd5e40