This is some of my coding..could you comment ?. I read the record length as $length = unpack "C4", substr $data,0,2,'';. is it correct ?
read (DATA, $data, 3);
$tag    = unpack "H2", substr $data,0,1,'';

if ($tag =~ /(81|80|00)/) {
    # the Record Identifier H’80 is used as Filler record to fill in o
+ne byte
    if ($tag == "80") {
        $length = 2;
    }

    # the Record Identifier H’81 is used as Filler record to fill in s
+everal bytes
    if ($tag == "81") {
        $length = unpack "C4", substr $data,0,2,'';
        $length -= 3;
    }

    # the Record Identifier H’00 is used as Filler record to fill in 3
+2 bytes
    if ($tag == "00") {
        $length=62;
    }

    read (DATA, $data, $length);
    $raw = unpack "H*", $data;

    if ($trace) {
        print  ("FILLER\n");
        printf ("%-20s : %-5s\n", "TAG", $tag);
        printf ("%-20s : %-5s\n", "RECORD LENGTH", $length);
        print  ("RAW DATA : \n$raw\n");
    }
}

[download]

In reply to Re^2: How to sort record using pack function ? by bh_perl
in thread How to sort record using pack function ? by bh_perl

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.