perl 两个文件字符串比较

#!/usr/bin/perl
#use strict;
open(FILE1,"C:/Perl/BX/BX-Users.txt");
open(FILE2,"C:/Perl/BX/BX-Book-Ratings.txt");
open(result1,">C:/perl/BX/BX-Users_result.txt");
my $i=0;
my $j=0;
while((my $bxUser=<FILE1>)&&($i<10))
{
        my $userId=substr($bxUser,0,index($bxUser,","));
        while(my $rankUser=<FILE2>)
        {
                my $userIdCmp=substr($rankUser,0,index($rankUser,","));
                if(($userId==$userIdCmp)&&($j==0))
                {
                        syswrite(result1,"$bxUser");
                        $j++;
                }

        }
        $j=0;
        $i++;
        
}
close(FILE1);
close(FILE2);
close(result1);