Like davorg and shmem, I am not sure what it is you are trying to do. Perhaps you could supply a data sample as well as the code you have tried so far and your expected output.

I have had a stab at my best guess making the assumption that your data, although possibly hundreds of records, is still small enough to fit in memory. Thus I am "slurping" the entire data file into memory. If your file is too large this may not be an option. I have annotated the code with (hopefully) explanatory comments. My example data uses just three header lines to illustrate the code in order to save space. Here it is

use strict;
use warnings;

# Set up start and end record sentinels.
#
my $startSentinel = q{**start record**};
my $endSentinel   = q{**end record**};

# Compile regex to pull out records. Note the
# \Q ... \E to quote regex metacharacters if your
# record start and stop sentinels contain them.
#
my $rxExtractRecord = qr
   {(?xms)
      \Q$startSentinel\E\n
      (.*?)
      (?=\Q$endSentinel\E\n|\z)
   };

# Slurp file into string; I'm using the <DATA>
# filehandle but you would open your file and
# slurp that.
#
my $completeFile;
{
    local $/;
    $completeFile = <DATA>
}

# Do a global match against compiled regex to
# pull out records and put them in an array.
#
my @records = $completeFile =~ m{$rxExtractRecord}g;

# Process each record in a loop.
#
foreach my $record (@records)
{
    # Split record up into 4 items on newline. I
    # have used 4 here as I have only put three
    # headers in my data for brevity. Get the data
    # part by pop'ing the last item off the @items
    # array so that @items only contains the
    # headers
    #
    my @items = split m{\n}, $record, 4;
    my $data = pop @items

    # This is where your specification becomes a
    # bit vague. Perhaps you would pull the name out
    # of the hdr1:... line and open two files, e.g.
    # fred.hdr and fred.dat and do a printf of the
    # headers to the first and a print of the data
    # to the second. You would open, print and close
    # the files in this loop. Perhaps your mention
    # of assignment means you want to transform the
    # headers in some way before do a printf.
    #
    ..... do something we can't guess here .....
}

__END__
**start record**
hdr1:fred
hdr2:2002-10-15
hdr3:head honcho
and here is some date
about fred telling us all
what a great guy he is
**end record**
**start record**
hdr1:pete
hdr2:2005-03-22
hdr3:bottle washer
not much data for pete
**end record**
**start record**
hdr1:mary
hdr2:2004-01-31
hdr3:personal assistant
mary is a great asset to the company
and will go far
**end record**
[download]

Hopefully this and the other responses will get you started.

Cheers,

JohnGG

Update: Used variables to hold start and end sentinels.