Please use the <code>...</code> tags around perl code - it makes it a lot easier to read.

Not knowing what kind of variation there could be in other messages of this type, I would take the following conservative approach to parsing it: 

if (m/Reply issued by (.*?):(.*)/) {
  my $issuer = $1;
  my $msg = $2;
  if ($issuer =~ m/([^\\]+)@/) {
    $issuer = $1;
  }
  $msg =~ s/\A\s*'\(ACK\)\s*//;
  $msg =~ s/\s*'\s*\z//;
  # results are in $issuer and $msg
} else {
  # not a Reply issued by message
}

[download]
The idea is to match the issuer and message sections and then trim each appropriately. If there happen to be similar messages which don't conform exactly to this format, at least you'll get something back.

Update: Changed \a in regex to \A - thanks moritz!

In reply to Re: regular expression issue by pc88mxer
in thread regular expression issue by sumesh.sasi

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.