perl中的奇怪符号

#! /usr/bin/perl
use strict;
use utf8;

#1  符号:$&   $`  $‘
my $str="my name is  hello world,and  her name  is hello world";
if($str=~m/name/g){
    print $`,"\n";#匹配到的字符串的前面部分
    print $‘,"\n";#匹配到字符串的后面部分
    print $&,"\n";#匹配到的字符串
}

#result:
my
 is  hello world,and  her name  is hello world
name