That doesn't compute. What is the input you have, and what is the output you want? How do I post a question effectively?

Ok sorry for an unclear question here my problems I have 3 files : source.txt, target.txt and data. Data file contain 2 column separate by :, example for code below is /hang:code1 /hung:code2 /hong:code3 then source.txt is file text that I want to process it, I need to read all lines and compare to the data file, the source.txt is guarantee have code such as \hang \hung \hing etc (left side code from data file) then those code are replace by code1, code2 etc and write to target file ( target.txt)

#!/usr/bin/perl
use strict;
use warnings;

my $filename = 'data';
my $sfilename = 'source.txt';
my $tfilename = 'target.txt';
open(DFILE, $filename) or die "Could not read from $filename, program 
+halting.";
open(SFILE, $sfilename) or die "Could not read from $filename, program
+ halting.";
open(TFILE, "> $tfilename") || die("Cannot Open File");
while(my $SBR=<DFILE>) {
        my @fields = split(':', $SBR);
        my $rRegex = qr/$fields[0]/;
        my $Regexr = qr/$fields[1]/;
        for my $s (qw(/hang /hung /hing /heng)) { #here I need read it
+ as a source file, compare to data file
         if ($s =~ $rRegex){
         print TFILE "$fields[1] "; # then write it to target file
         }
        }
}
close DFILE;
close SFILE;
close TFILE;
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wa2nlinux:

You don't need to. I used qw just for making the example. Perhaps I should've written it like this:

#!/usr/bin/perl
use strict;
use warnings;

my $r = "ab+c*d";
my $rRegex = qr/$r/;
while (my $t = <DATA>) {
    if ($t =~ $rRegex) {
        print "MATCH: $t\n";
    }
}
__DATA__
abcd
aabbbd
acccd
dbca
[download]

...roboticus

When your only tool is a hammer, all problems look like your thumb.