Thank you very much for your help, but after I turn my code into a function, I still can't figure out how to read all the files and replace the extension...I wrote something like this: 

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

sub process_file
{
  my ($original, $final) = @_;

  open( my $original_fh, "<", $original ) or die $!;
  open( my $final_fh,    ">", $final )    or die $!;

  my $first = <$original_fh>;
  print $final_fh $first;
  my @replace = $first =~ /"([^"]*)"/g;

  while (my $line = <$original_fh>) {
    print "Enter the desired number of columns: ";
          my $nr = <STDIN>;
          chomp($nr);
    $line =~ s/((\w\w\t){$nr})/$1\n/g;
    $line =~ s/\t/,/g;
    $line =~ s/(\d{2})/$replace[$1]/g;
    print $final_fh $line;
  }

  close $original_fh;
  close $final_fh;
}

my @files = glob '*.txt';
my $new_file = $name =~ s/txt$/csv/r;
process_file($files, $new_file);

[download]

but I know it can't run...I didn't quite understand how can I use the substitution that you wrote because I know that $name is not declared. I appreciate any advice you can give me!

In reply to Re^2: Read from multiple files change the data with a script and the write the respective output files with a different extension by Akatsuki
in thread Read from multiple files change the data with a script and the write the respective output files with a different extension by Akatsuki

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