Smith has asked for the wisdom of the Perl Monks concerning the following question:

I am doing a nested while loop with filehandlers and getting massive redundancies. Can anyone help me with this?

ActiveStatePerl 5.10.0 Build 1004 (free version)
Coding on WXP using VIM for Windows (unfortunately)

I have a file that contains a list of files and md5hashes.

This is the first while loop using a file handler. A real file will have 200 lines or so.
(sample file list BADFILES.csv)
let.exe,FFA9C229DE8F66776EFCBA90086877F7,C:\,18944KB,ticket

Im connected to hosts and doing a filescan and for this test the host has the file located in three directories. I was unable to regex this as a variable it would only grab the first c:\ due to the format. So I dumped it to FSOUT.txt and created a second while loop doing a filehandler. This works perfect and grabs all three but created redundancies.
(sample output FSOUT.txt)

Attempting to connect to remote host...
Initialising rctrlx server component...
Executing remote application: filescan.exe let.exe
Stdout:

 Volume in drive C has no label.
 Volume Serial Number is 6C3D-BD57

 Directory of c:\

02/04/2009  11:26 AM                 0 let.exe
               1 File(s)              0 bytes

 Directory of c:\WINDOWS

02/04/2009  11:31 AM                 0 let.exe
               1 File(s)              0 bytes

 Directory of c:\WINDOWS\system32

02/04/2009  11:31 AM                 0 let.exe
               1 File(s)              0 bytes

     Total Files Listed:
               3 File(s)              0 bytes
               0 Dir(s)  27,333,230,592 bytes free

Remote application exited with code: 0

[download]
Here is the snippet of code with the nested while loops. #!C:\\Perl\\bin\\perl.exe

my $workdir = "c:\\MalwareScanner\\lclscn";

if (! $ARGV[0]){
    print "FATAL Didnt get an IP address\n";
    $target = <>;
} else {
    $target = $ARGV[0];    
}

$badfiles = "$workdir\\BADFILES.csv";
$fsout = "$workdir\\FSOUT.txt";
open (BADIN,$badfiles);
open (FSOUT,">$fsout");
print HOSTINFO "File,MD5,Ticket,Size,Path\n";
while (<BADIN>){
        chomp();
        $badline = $_;

        if ($badline =~ /(.+?),(.+?),.+?,.+?,(.+)/){
                $file = $1;
                $hash = $2;
        $tckt = $3;
        }
    
    $filescan = `rctrlx.exe $target /u "domain\\username" /p "password
+" /c filescan.exe /app filescan.exe $file`;
    print FSOUT $filescan;

    if ($filescan =~ /(error.*)/i){
        $scanerror1 = $1;
        print ERROR "$logdate,$logtime,$target,$host,Could not run fil
+escan.exe remotely on target host,$scanerror1\n";
    }
    if ($filescan =~ /(.*\d{10})/){
        $scanerror2 = $1;
        print ERROR "$logdate,$logtime,$target,$host,Could not run fil
+escan.exe remotely on target host,$scanerror2\n";
    }

    close FSOUT;
    $fsin = "$workdir\\FSOUT.txt";
    open (FSIN,$fsin);
    while (<FSIN>){
        chomp();
        $fsline = $_;
        
        if ($fsline =~ /(.:\\.*)/){
            $dir = $1;
            print "XXXX$dir\n";
        }
        if ($fsline =~ /1\sFile\(s\)\s+(.*)/){
            $size = $1;
            $size =~ s/[\s]//g;

            $scanned = "$logdir\\SCANNED.csv";    
            open (SCANNED,">>$scanned");    
            print SCANNED "$logdate,$logtime,$target,$host\n";
        }        
    
        print "$dir\n";
        
        $badhost = "$logdir\\BADHOST.csv";
        open (BADHOST,">>$badhost");
        $dest = "$dir\\$file";
        $dest =~ s/[\s]//g;
        $md5sumtmp = `rctrlx.exe $target /u "domain\\username" /p "pas
+sword" /c md5sum.exe /app md5sum.exe $dest`;

        if ($md5sumtmp =~ /([a-z0-9]{32})/){
                $md5sum = $1;
        }
            if ($md5sum eq $hash){
                print HOSTINFO "$file,$md5sum,$tckt,$size,$dir\n";
            print BADHOST "$logdate,$logtime,$target,$host,$file,$md5s
+um,$tckt,$size,$dir\n";
        }
    }
}

[download]
Notice I have two print to STDOUT for testing:
[print "XXXX$dir\n";]
[print "$dir\n";]

[download]
This is what I get when I run it against the host with the files.

\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
XXXXc:\
c:\
c:\
c:\
c:\
c:\
XXXXc:\WINDOWS
c:\WINDOWS
c:\WINDOWS
c:\WINDOWS
c:\WINDOWS
c:\WINDOWS
XXXXc:\WINDOWS\system32
c:\WINDOWS\system32
c:\WINDOWS\system32
c:\WINDOWS\system32
c:\WINDOWS\system32
c:\WINDOWS\system32
c:\WINDOWS\system32
c:\WINDOWS\system32
c:\WINDOWS\system32
c:\WINDOWS\system32
c:\WINDOWS\system32

[download]
What I need is just the three directory listings c:\ , c:\WINDOWS , c:\WINDOWS\system32.

Replies are listed 'Best First'.
Re: Nested While Loop Problem
by kennethk (Abbot) on Feb 05, 2009 at 21:32 UTC

    You should always start every script with use strict; use warnings;. These are very good ways of avoiding a lot of pointless headaches.

    You could achieve your goal in a fairly straight forward way using hashes. Replace the print statements in your while loop with $count{$dir}++;, which will increment a directory-specific counter. You can then finish your script with print join "\n", keys %count;. For some information on hashes, check out perlintro.

[reply]
[d/l]
[select]
      Thank you very much. Im still a little green on hashes and wasnt sure if it would work in this situation without introducing yet another loop.

      I had the two print statements to show that it prints fine from within the if statement. (it gives me the three directories like it should) 
      if ($fsline =~ /(.:\\.*)/){
   $dir = $1;
   print "$dir\n";  #works fine here
}

      [download]
      But if I print outside of the if statement I get the redundancies. And if there are then this command will repeat against the remote host multiple times for the same directory.

      $badhost = "$logdir\\BADHOST.csv";
open (BADHOST,">>$badhost");
$dest = "$dir\\$file";  #will print redundancies here
$dest =~ s/[\s]//g;
$md5sumtmp = `rctrlx.exe $target /u "domain\\username" /p "password" /
+c md5sum.exe /app md5sum.exe $dest`;

      [download]
[reply]
[d/l]
[select]
        I am having a little difficulty interpreting your question, so if this answer is off point I apologize. I think what is happening is that since you are accessing the $dir variable outside of the conditional loop, you are caching a value of $dir from a previous traverse of the loop. Perhaps this could be fixed with something along the lines of

        if ($fsline =~ /(.:\\.*)/){
    $dir = $1;
    print "$dir\n";  #works fine here
} else {
    next;
}

        [download]

[reply]
[d/l]

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