• The lines

      %file2 = 'Source.txt' ;
      open(INFO, "<%file2" ) ;
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  is incorrect. You should use a '$' here, not a '%', since file2 is holding a simple string. For that matter, you could reuse $file1 from the previous block of code, or do without storing the filename in a variable altogether:

      open(INFO, '<Source.txt');
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• You're not verifying that any of the open() calls succeeds.
• You're not removing end-of-line characters from any of the lines you're reading.
• You're comparing strings containing only IP addresses (from the first file) to strings containing IP addresses and country names (from the second file). You're unlikely to find any matches.

    my %table;
    open(IN, '<Source.txt') or die;
    while (<IN>) {
        chomp;
        my($ip, $country) = split(' ', $_, 2);
        $table{$ip} = $country;
    }
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Once you've done that--and assuming you've removed newlines from your input data--you can do country lookups like this:

    open(OUT, '>>conversion.txt') or die;
    foreach $line1 (@lines1) {
        if (exists $table{$line1}) {
            print OUT $line1, ' ', $table{$line1}, "\n";
        }
    }
    close OUT;
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Thanks everyone for your help. I had wondered about using a %file, but I wanted a 2 dimentional array, so figured that would be how to get one. :/ I have taken out reading into $file, and opened the list straight into INFO, and gone with a hash table. My teammates asked that I print the IP if I couldn't find it in the table, so I added an else. I'm still working on the hash table, to make sure I don't need more than those 2 fields. Its been over 10 years since I did any Perl scripting, so I am WAY out of practice! Here is the second interation of code: #!/perl # open(INFO, '<IPs.txt' ) or die; @lines1 = <INFO> ; close(INFO) ; my %table open(IN, '<source.txt' ) or die; while (<IN>) { chomp; my($ip, $country) = split(' ',$_,2); $table($ip) = $country; } open(OUT, ">>conversion.txt") or die; foreach $line1 (@lines1) { if (exists $table($line1)) { if $line2 =~ /$line1/ ; print OUT $line1, ' ',$table($line1),"\n" ; else else print OUT $line1; } } close OUT;

Uhm... some things to point out here

First, you don't use strict, and it hurts :-); it would have catched, for example:

which is an error, twice. First, because you are using an hash instead of a variable; second, because you are assigning an odd number of elements to an hash

Second, you are slurping two files into memory, and that could be a pain if the files are too big, compared to your memory; probabily, you could do with reading one of the two line per line, and cache the other.

Third, you have three cycles, put probabily you could just grep; more on this later, because there is a badder thing before:

You open and close conversion.txt over and over: that is expensive! Why don't just open(APPEND, ">>conversion.txt") ; on top, close(APPEND); on bottom and print(APPEND "$line2") ; (watch the unbalanced parenthesis on that line!) when required?

You are comparing $line1 and $line2 with !=: that's a numerical comparison. If you want to do the same test on strings, you should use ne instead.

And now about the cycles: one way to compact them could be:

foreach my $line1 (@lines1) {
  print APPEND grep $line1 ne $_,@lines2 ;
}
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Take a look at the documentation (perldoc -f grep) to know more about grep

Apart of the errors, keep studying perl. Maybe your program is not that good still, but it seems to me you are headed in the right direction ;-)

Ciao!
--bronto

%file2 = 'Source.txt' ;      # Name the file with source addresses
open(INFO, "<%file2" ) ;     # Open the file
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$file2 = 'Source.txt' ;      # Name the file with source addresses
open(INFO, "<$file2" ) ;     # Open the file
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open APPEND, ">>conversion.txt";
foreach $line1 (@lines1) {
   foreach $line2 (@lines2) {
      print APPEND $line2
         if $line2 =~ /$line1/;
   }
}
close APPEND;
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The code

    print APPEND $line2
         if $line2 =~ /$line1/;
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is not a good way to look for an IP address in a line of text. First of all, it will match when you're searching for an IP that's a substring of the one contained in the text:

    $line1 = '1.2.3.4';
    $line2 = '111.2.3.44';
    print "match\n" if $line2 =~ /$line1/;
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Second, the periods in IP address strings will be interpreted as regular expression metacharacters:

    $line1 = '1.2.3.4';
    $line2 = '11223344';
    print "match\n" if $line2 =~ /$line1/;
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-caedes

If you aren't bound to your list of IP/countries, you can try with Geo::IP.

BTW, practice makes perfect; I learned Perl this way, building small utilities.

Happy working, Valerio