The appropriate solution to this problem depends on how precise the pattern matching needs to be. How much post-extraction processing you are willing to do matters as well, e.g. do you need '58bn5904' or are you content with 'd:\data\58bn5904.dat'.

To give you an idea of how ugly the regex could become: 

use strict;
use warnings;

# Example line:
# e:\logfiles\beardstownbase.log [3] Thu 22Jun06 08:07:19 - (006415) S
+ent file d:\data\58bn5904.dat successfully (25.0 Kb/sec - 859216 byte
+s)
# Desired:
# beardstownbase,Thu 22Jun06 08:07:19,58bn5904,859216 bytes

my $re_date = qr<
        (?:Sun|Mon|Tue|Wed|Thu|Fri|Sat)
        \s
        \d{1,2}              # Day of month
        (?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec) # Month
        \d{2}                # Two digit year
        \s
        \d{2}:\d{2}:\d{2}
>x;

my $pattern = qr<
      e:\\logfiles\\(.*?)  # Capture(1) filename
      \s
      \[\d+\]              # Bracketed number
      \s
      ($re_date)           # Capture(2) date
      \s - \s
      \(\d+\)              # number in parens
      \s
      Sent \s file \s
      d:\\data\\(.*?)\.dat      # Capture(3) file basename           
      \s
      successfully
      \s
      \(
        [0-9.]+
        \s
        [A-Z]b
        /sec
        [ ] - [ ]
        (\d+ \s bytes)     # Capture(4) bytes text
      \)
>x;


while (my $line = <DATA>) {
    if ($line =~ /$pattern/) {
        my ($logfile, $date, $file_basename, $bytes) = ($1,$2,$3,$4);
        printf "(%s) (%s) (%s) (%s)\n", $logfile,$date,$file_basename,
+ $bytes;
    }
}



__DATA__
e:\logfiles\beardstownbase.log [3] Thu 22Jun06 08:07:19 - (006415) Sen
+t file d:\data\58bn5904.dat successfully (25.0 Kb/sec - 859216 bytes)

[download]
I have been meaning to learn Parse::RecDescent for ages, so tonight I took some time to try and solve your problem with it. It is likely the wrong tool for this job, and definitely a poor implementation - I would welcome any feedback for people with stronger parse-fu. 
use strict;
use warnings;
use Parse::RecDescent;
$::RD_HINT=5;

my $grammar = <<'GRAMMAR';
  { 
    use strict;
    use warnings;
  }     
          
  logfile : 'e:\\logfiles\\' /[-A-Za-z0-9_.]+/ 
            { $item[2] }
  
  date : 
    m{
        (?:Mon|Tue|Wed|Thu|Fri|Sat|Sun)
        \s
        \d\d
        (?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)
        \d\d
    }x
  
  time  : /\d{2}:\d{2}:\d{2}/ 

  sentfile: 
    <skip:''>
    'd:\\data\\'
    /[-A-Za-z0-9_]+/
    '.dat'
    { $item[3] }

  
  rate  : /\d+\.\d [A-Za-z]+\/sec/
  
  bytecount : /\d+ bytes/
  
  parse : 
    logfile 
    /\[\d+\]/
    date
    time
    /- \(\d+\) Sent file /
    sentfile
    <skip:'[- \t()]*'> (
        /successfully/
        rate
    )
    bytecount
  { [ @item{qw(logfile date time sentfile bytecount)}] }


GRAMMAR
# Expect: beardstownbase,Thu 22Jun06 08:07:19,58bn5904,859216 bytes
my $parser = Parse::RecDescent->new($grammar);
use Data::Dumper;
while (my $line = <DATA>) {
    last unless $line =~ /\S/;

    my @fields = $parser->parse($line);
    if (@fields) {
        print Dumper \@fields;
    }

}

__DATA__
e:\logfiles\beardstownbase.log [3] Thu 22Jun06 08:07:19 - (006415) Sen
+t file d:\data\58bn5904.dat successfully (25.0 Kb/se

[download]
Output: 
$VAR1 = [
          [
            'beardstownbase.log',
            'Thu 22Jun06',
            '08:07:19',
            '58bn5904',
            '859216 bytes'
          ]
        ];

[download]

In reply to Re: Regex Help - Large regex example, and larger Parse::RecDescent attempt by imp
in thread Regex Help pulling Data from a string by batcater98

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