A perl script that dumps the number of time each character in a tree of source files appears

gistfile1.txt

use strict;
use File::Find;
use Data::Dumper;

my @ext = qw(\.c \.h \.cpp \.hpp);

my %stats;

sub search
{
    foreach my $ext (@ext)
    {
        #if (index(, $ext) != -1)
        if( $File::Find::name =~ /$ext$/  )
        {
            local $/;
            open my $source, "<", "$File::Find::name"
                or die "cannot open < $File::Find::name: $!";
            print "$File::Find::name\n";
            my $filestring = <$source>;
            for (my $i = 0; $i < length($filestring); $i++)
            {
                my $c = substr $filestring, $i-1, 1;
                $stats{$c} += 1 if (exists $stats{$c});
                $stats{$c} = 1 if !(exists $stats{$c});
            }
            close $source
                or warn "failed to close $File::Find::name: $!";
        }
    }
}

if (scalar(@ARGV) > 1)
{
    print "./$ARGV[0]\n./$ARGV[1]\n";
    find({ wanted => \&search, no_chdir => 1 }, "./$ARGV[0]");
    open my $dump, ">", "./$ARGV[1]"
        or die "cannot open > ./$ARGV[2]: $!";
    print $dump Dumper(\%stats);
}