# ..\perl.exe
# perlmonks http://perlmonks.org/index.pl?node_id=951536
# Text::CSV witer

use strict;
use warnings;


use Text::CSV;

my $input_file = "951536_in.csv";
my $output_file = "951536_out.csv";

 my @rows;
 my $csv = Text::CSV->new ( { binary => 1 } )  # should set binary attribute.
                 or die "Cannot use CSV: ".Text::CSV->error_diag ();


#read file 
 open my $fh, "<:encoding(utf8)", $input_file or die "$input_file: $!";
 while ( my $row = $csv->getline( $fh )) {
     $row->[0] =~ s/^(.*)(\d+)$/abc$2/; # replace leading chars
     $row->[1] =~ s/^(.*)(\d+)$/$1asd$2/; # insert between char and digit
     $row->[2] =~ s/^(.*)(\d+)$/$1xyz/; # replace digits
     push @rows, $row;
 }
 $csv->eof or $csv->error_diag();
 close $fh;


#write file
$csv->eol ("\n");
open my $fh_out, ">:encoding(utf8)", $output_file or die "$output_file: $!";
 $csv->print ($fh_out, $_) for @rows;
 close $fh_out or die "$output_file: $!";


 print "finish!\n";