"It doesn't work" does not help us to help you - please provide any error messages you are getting, and/or describe how the program currently behaves and how you'd like it to behave.

Having said that, in your map you don't need the semicolon in /\|/;, since there is another argument to split ($_) following the regular expression, the statement doesn't end there. You said you are a Perl beginner, so have a look at perlintro (and perlsyn).

To help your further could you provide a sample of what the three files (2x input 1x output) currently look like, and an example of how you'd like them to look? You can also edit your original post to include this information, see How do I change/delete my post?

Hi, sorry, I'll try to be more detailed: I have a file we can call it Input.txt like the following

Input.txt
2014-04-24 14:22:52|TESTER001||/dev/pts/5|322655663|TYXRRES|0
2014-04-24 14:22:52|TESTER003||/dev/pts/5|323231258|TRRRDER|0
2014-04-24 14:22:52|TESTER002||/dev/pts/5|323135368|RCVDDER|0
[download]

And I need to operate a secific substitutions using a "map" the script can found in Changes.txt

Changes.txt
 TESTER001,Frank_Sinatra
 TESTER002,Jhon_Belushi
 TESTER003,Homer_Simson
[download]

After the changes the output should look like this:

Output.txt (desired)
2014-04-24 14:22:52|Frank_Sinatra||/dev/pts/5|322655663|TYXRRES|0
2014-04-24 14:22:52|Homer_Simson||/dev/pts/5|323231258|TRRRDER|0
2014-04-24 14:22:52|Jhon_Belushi||/dev/pts/5|323135368|RCVDDER|0
[download]

but the real Output.txt is different from my idea:

 real Output.txt
2014-04-24 14:22:52 Frank_Sinatra  /dev/pts/5 322655663 TYXRRES 0
2014-04-24 14:22:52 Homer_Simson  /dev/pts/5 323231258 TRRRDER 0
2014-04-24 14:22:52 Jhon_Belushi  /dev/pts/5 323135368|RCVDDER|0
[download]

So what I got is the right substitution but even an extra substitution of the | with a white space..... Here hte code i use

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

open( my $out_fh, ">", "Output.txt" ) || die "Can't open the output fi
+le for writing: $!";

open( my $address_fh, "<", "Changes.txt" ) || die "Can't open the Chan
+ges file: $!";

my %lookup = map { chomp; split( /,/, $_, 2 ) } <$address_fh>;

open( my $file_fh, "<", "Input.txt" ) || die "Can't open the Input.txt
+ file: $!";
while (<$file_fh>) {
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I think my problem is in the following Line...

  
 my @line = split( /\|/, $_,);
    for my $char ( @line ) {
        ( exists $lookup{$char} ) ? print $out_fh " $lookup{$char} " :
+ print $out_fh " $char ";
    }
    print $out_fh "\n";
}
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Thank you

my @input = split /\|/, $_;   # we've split the input line into fields
+ - the "|" are gone now

my @output = @input;
$output[1] = $lookup { $output[1] } // $output[1];  #map the second fi
+eld

print $out_fh join("|", @output); # put the "|" back in
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CAUTION: untested