Need to pull matched string plus a few additional bytes

I am working on my very first program and have run into a bit of a
roadblock. I am trying to print a report of users who show up in an IIS
Log file. The good news is that the format of the userid is
WINDOWSDOMAIN\USERID. The bad news is that it is not always at the same
place in the IIS Log file due to some variable length fields that come
before it. Its location can vary left or right by about 10 bytes.



I read the IIS Log file in one line at a time. I have gotten far enough
that I can identify the lines with WINDOWSDOMAIN on it, but am stuck
there. The code $userid = substr($logfile_in, 33, 12); gets me close
but depending on the length of the date, the time or the IP address, it
is usually off by a few bytes. A sample of the input is below to
explain what I am talking about.



2006-10-23 12:08:47 24.32.35.123 WINDOWSDOMAIN\USERID 175.128.127.43 80
GET /itd/styles/main.css

2006-10-23 12:08:47 24.32.35.123 WINDOWSDOMAIN\USERID 175.128.127.43 80
GET /itd/styles/contents.aspx

2006-10-23 12:08:47 24.32.35.123 WINDOWSDOMAIN\USERID 175.128.127.43 80
GET /itd/styles/footer.aspx



Essentially what I need to do is find the WINDOWSDOMAIN on a line, and
write to a file the matched string plus \USERID data (up to the next
space). Does anyone have any suggestions? I'm thinking there must be
some very easy way to do it since Perl is made for this sort of thing.
I remember reading about some Perl built-in capability that would take a
scalar variable and parse it into an array based on a delimiter, but I
can't remember what it is. That would probably do it for me. But if
you know of a better way, I'm all ears.



Below is the code I am using.





# My first PERL program.



open USERIDOUT, ">userid.out.txt";

open IISLOG, "<ex061023.log";



$ctr = 0;

$hit_counter = 0;

$miss_counter = 0;

$logfile_in;

$userid;



while (<IISLOG>)

{

$logfile_in = $_;

if ( ($logfile_in =~ m/WINDOWSDOMAIN/i && $logfile_in =~
m/itd/i)

)

{

print "\n** Found success\n";

$hit_counter += 1;


$userid = substr($logfile_in, 33, 12);
# This is not correct but is somewhat close

print "\n", $userid;


}

else

{

print "Did not find success\n";

$miss_counter += 1;

}

}



print "\n Hit Counter = ", $hit_counter;

print "\n Miss Counter = ", $miss_counter;

print "\n Total Records Counter = ", $hit_counter + $miss_counter;



close USERIDOUT;

close IISLOG;





*****************************************************

Phil
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