use File::Find;

find(\&wanted,'.');

print "Total = $counter\n";
sub wanted
{
    if ($_ =~/(?:\.pl|\.pm)/)
    {
        open (my $fh,"<",$_) or die "$!";

        while (<$fh>)
        {
           if ($_ =~/^sub\s+/){$counter++}
        }
        close $fh;
    }
}
[download]

It reported 5394 subs. Importing that lot could use a *lot* of RAM, and take a while to compile ;-)