一个统计txt文档中 单词出现次数的小程序，方便背单词

#!/usr/bin/perl
use Data::Dumper;
$words;
$/=undef;
open FILE,"/tmp/harry";
chomp($content=);
while ($content){
        if ($content=~/\w+/){
                if (exists $$words{$&}){
                        $$words{$&}++;
                }else{
                        $$words{$&}=1;
                }
                $content=$';
        }else{
                last;
        }
}
close FILE;
@keys = sort { $$words{$b} <=> $$words{$a} } keys %$words;
for (@keys){print "$_ -> $$words{$_}\n"};

用它统计哈利波特第一季，排名前十的高频词：
the -> 3315
to -> 1851
and -> 1812
a -> 1581
Harry -> 1326
of -> 1250
he -> 1209
was -> 1178
in -> 935

只出现过一次的单词有2989个

总共使用了6658个单词