perl的输入输出有关问题

perl的输入输出问题

use strict;
use warnings;
use diagnostics;
my (@words, %count, $word);
 
chomp(@words = <STDIN>);
foreach $word(@words)
{
  $count{$word} += 1;
}  
foreach $word(keys %count)
{
  print "$word was seen $count{$word} times.\n";
}  


请问为什么运行了程序以后一直停留在输入的状态中，如何让输入结束且运行程序

[解决办法]
unix 下用 ctrl + D