Hey every body Thank you for any advice you could gave me. I need write a program from scratch which seems particularly difficult to me (I have just started learning Perl....). So the problem is I have 2 data files (quite huge basically 1 GB). I need to retrive some data on file 2 using a list created on file 1. Basically file 1 is a txt wih different info on it from which I need to get a list of values (basically the values are separated by tab or by colon). I wrote a code which is : 
#!/usr/bin/perl -w
use strict;
my$line;
my@fields;
my@output;
open (FILE, 'XXXX.txt') or die "can't open the file: $!";
open (FD, '>XXXX.txt') or die "can't open the file: $!";
while (defined ($line= <FILE>)) {
my@fields= split (/\s/ ,$line);
my@output = grep /rs\d{5,}\b/ ,@fields;
my$rs = join (':' , @output);
$rs=~ s/:/\n/g;
print FD "$rs";
}
close FILE;
close FD;

[download]
This was just to look at the result The values I need to search from the file 1 are now in the array my@output. Now for each of these elements I would like to search a second txt file and grab the string that contains the element. DO you think grep can work on that? If not you have a better idea? Thanks for the help Micky

In reply to General program and related problems by micky744monk

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