local $/ = '';
my $date = qr/\d\d\.\d\d.\d\d\d\d/;
my $fee  = qr/\d\d\d\d\d\.\d\d/;
my $one  = qr/
    ^
    \d\d        #record10           = integer (length 2) (10).
    (\d{5})     #primary key        = integer (length 5).(00001)
    (\d{3})     #sub item number    = integer (length 3).(225)
    ($date)     #start date         = dd.mm.yyyy.(01.11.1996)
    ($date)     #end date           = dd.mm.yyyy.(00.00.0000)
    (\w{3})     #category           = alphanumeric (length 3).(BVF)
    (\w{3})     #group              = alphanumeric (length 3).(AAA)
    (\w{3})     #subgroup           = alphanumeric (length 3).(A65)
    ([SN])      #item type          = text (options: S or N).(S)
    ([ND])      #fee type           = text (options: N or D).(N)
    (\w{3})     #provider type      = alphanumeric (length 3).(009)
    ([YN])      #new item           = text (options: Y or N).(Y)
    ([YN])      #item change        = text (options: Y or N).(N)
    ([YN])      #procedure change   = text (options: Y or N).(Y)
    ([YN])      #description change = text (options: Y or N).(N)
    ([YN])      #fee change         = text (options: Y or N).(Y)
    $
/x;

my $two = qr/
    ^
    \d\d    #record20 = integer (length 2).(20)
    ($date) #start date = dd.mm.yyyy.(01.11.1996)
    ($fee)  #fee = decimal (nnnnn.nn).(00098.05)
    ($fee)  #benefit1 = decimal (nnnnn.nn).(00073.55)
    ($fee)  #benefit2 = decimal (nnnnn.nn).(00083.35)
    $
/x;

my $gen = qr/
    ^
    \d\d
    ($date)
    (.*)
    $
/x;

while(my $rec = <DATA>) {
    my $pkey, 
    my @out = ();
    for my $line( split /[\n\r]/, $rec ) {
        my $type = substr $line,0,2;
        if ( $type == 10 ) {
            my @data = $line =~ m/$one/;
            $pkey = $data[0];
            @out[$type] = join ',', $pkey, $type, @data;
        }
        elsif ( $type == 20 ) {
            my @data = $line =~ m/$two/;
            @out[$type] = join ',', $pkey, $type, @data;
        }
        elsif ( $line =~ m/$gen/ ) {
            my @data = ( $1, $2 );
            if ( defined $out[$type] ) {
                $out[$type] .= ' ' . $2;   # continuing string
            }
            else {
                $out[$type] = join ',', $pkey, $type, @data;
            }
        }
        else { 
            die "Invalid record $rec\n\n$line\n" 
        }
    }
    print join "\n", @out[10,20,30,40,50];
    print "\n";
}

__DATA__
100000122501.11.199600.00.0000BVFAAAA65SN009YNYNY
2001.11.199600098.0500073.5500083.35
3014.11.1996This derived fee is for professional attendances for GP and Specialist.
4023.12.1996(Anaes.)
5001.11.1997Professional attendance being an attendance at
5001.11.1997other than consulting rooms, by a general
5001.11.1997practitioner on not more than 1 patient.

100000222601.11.199600.00.0000BDGAABA66SN010YNYNY
2001.11.199600098.0500073.5500083.35
3014.11.1996This derived fee is for professional attendances by GP only.
4023.12.1996(Anaes.)
5001.11.1997Professional attendance being an attendance at
5001.11.1997other than consulting rooms, by a general
5001.11.1997practitioner only on not more than 1 patient.