use strict;
    use warnings;
my @files=('data.txt');
   for my $input_file (@files) {
   my $output_file = $input_file.".out";


    process_file($input_file, $output_file);
}
sub process_file {
    my($input_file, $output_file) = @_;  
    my %count;

    my $file = shift or die "Usage: $0 FILE\n";
    open my $fh, '<', $file or die "Could not open '$file' $!";
    open my $fa, '>', $output_file;
$/="";
    while (my $line = <$fh>) {

    foreach my $str ($line) {
    chomp $line;

    
    $count{$str}++;

    }
    }

    foreach my $str (sort keys %count) {


    printf $fa "%-s %s", $str."\t", $count{$str};
    print $fa ":".$input_file."\n";
    }
}