perl 获取更新部分日志

#!/usr/bin/perl
#取文件行数
##循环开始清空文件
if (-f "tmp.out"){
open FILE,">tmp.out";
close FILE;}

open( A,"<","count.txt" );
            while (<A>) {
            $count = $_;
                        };
print "上次记录的记录数为$countn";


open(my $fh,'<','catalina.out');
$. = 0;
while (<$fh>) {
    ($num=$.) if eof;
};
print "文件最新的记录数为$num"."n";
    open( B,">","count.txt" );
    print B ("$numn");

if ( defined($count)  && $num != $count && $num !=0  )
{print "开始处理n";
     open( C,"catalina.out" ) || die "$!n";
       while (<C>) {
             if  ($. > "$count" ){ 
              open( D,">>","tmp.out" );
              print D ("$_n");
             }
}};