Perl 循环内没关闭文件句柄引发的问题

v-lhb-db01:/root/perl# cat 1.log 
1111
2222
3333
4444
5555
异常111
a1
a2
a3
a4
a5
java.lang.NullPointerException]
1
2
3
4
java.lang.NullPointerException
5
6
7
8

--------------------------------------------
#!/usr/bin/perl 
use POSIX;
my $dir  = '/root/perl';
my $file = '1.log';
$mon_file = "$dir/$file";
$IPMACHINE = "MBANKtest1";
$RTXNO="04657";
my $SDATE = strftime("%Y%m%d%H%M%S",localtime());
$UPLOADPATH = "/data/swap/mbanklog/$IPMACHINE-$SDATE$file";
print "########################################################################################################################
";
print "######监控日志文件：          $mon_file
";
print "######监控服务器：            $IPMACHINE
";
print "######报警通知腾讯通号码：    $RTXNO
";
print "######当前报警时间戳：        $SDATE
";

##########监控关键字，以空格隔开################
@warn_arr = qw/Exception 异常/;
foreach $a (@warn_arr) {
    undef @err_info;
    open( C, "<", "$a.tmp" );
    while (<C>) {
        $count = $_;
    }
print "=========================================================================================================================
";
print "######监控异常关键字：      "$a"---数量=$count
";
    open( A, "<", "$mon_file" ) || die "$!
";
    $i   = 0;
    $num = 0;
    $b = 0;
    while (<A>) {
        $num++;
        if ( $_ =~ /$a/i ) { $i++; $b = $num }
    }
    print "######$b is $b######
";
        if ( $i != 0 && $i == $count && defined($count) ) {
        open( B, "<", "$mon_file" ) || die "$!
";
        while (<B>) {
        if  (($. >= "$b" -2) and  ($. <= "$b" + 2) ){push( @err_info, $_ ) };
        };
        print "######错误信息：             @err_info
";
#        system("wget -q --spider -t 1 http://10.130.130.248:8012/sendnotify.cgi?title="$IPMACHINE"\&msg="$SDATE$file\n@err_info"\&receiver="$RTXNO"");
##        sleep(5);
##        system("./putlog "$mon_file" "$UPLOADPATH"");
#        print "######日志文件已上传至       $UPLOADPATH
";
#close B;
    }

    open( C, ">", "$a.tmp" );

    print C ("$i
");

}
--------------------------------------------


v-lhb-db01:/root/perl# perl m1.pl 
########################################################################################################################
######监控日志文件：          /root/perl/1.log
######监控服务器：            MBANKtest1
######报警通知腾讯通号码：    04657
######当前报警时间戳：        20150505101212
=========================================================================================================================
######监控异常关键字：      "Exception"---数量=2

######$b is 17######
######错误信息：             3
 4
 java.lang.NullPointerException
 5
 6

=========================================================================================================================
######监控异常关键字：      "异常"---数量=1

######$b is 6######
######错误信息：


这里异常的上下行没有打印,原因为没关闭文件句柄:

#!/usr/bin/perl 
use POSIX;
my $dir  = '/root/perl';
my $file = '1.log';
$mon_file = "$dir/$file";
$IPMACHINE = "MBANKtest1";
$RTXNO="04657";
my $SDATE = strftime("%Y%m%d%H%M%S",localtime());
$UPLOADPATH = "/data/swap/mbanklog/$IPMACHINE-$SDATE$file";
print "########################################################################################################################
";
print "######监控日志文件：          $mon_file
";
print "######监控服务器：            $IPMACHINE
";
print "######报警通知腾讯通号码：    $RTXNO
";
print "######当前报警时间戳：        $SDATE
";

##########监控关键字，以空格隔开################
@warn_arr = qw/Exception 异常/;
foreach $a (@warn_arr) {
    undef @err_info;
    open( C, "<", "$a.tmp" );
    while (<C>) {
        $count = $_;
    }
print "=========================================================================================================================
";
print "######监控异常关键字：      "$a"---数量=$count
";
    open( A, "<", "$mon_file" ) || die "$!
";
    $i   = 0;
    $num = 0;
    $b = 0;
    while (<A>) {
        $num++;
        if ( $_ =~ /$a/i ) { $i++; $b = $num }
    }
    print "######$b is $b######
";
        if ( $i != 0 && $i == $count && defined($count) ) {
        open( B, "<", "$mon_file" ) || die "$!
";
        while (<B>) {
        if  (($. >= "$b" -2) and  ($. <= "$b" + 2) ){push( @err_info, $_ ) };
        };
        print "######错误信息：             @err_info
";
#        system("wget -q --spider -t 1 http://10.130.130.248:8012/sendnotify.cgi?title="$IPMACHINE"\&msg="$SDATE$file\n@err_info"\&receiver="$RTXNO"");
##        sleep(5);
##        system("./putlog "$mon_file" "$UPLOADPATH"");
#        print "######日志文件已上传至       $UPLOADPATH
";
close B;
    }

    open( C, ">", "$a.tmp" );

    print C ("$i
");

}

v-lhb-db01:/root/perl# vi m1.pl 
v-lhb-db01:/root/perl# perl m1.pl 
########################################################################################################################
######监控日志文件：          /root/perl/1.log
######监控服务器：            MBANKtest1
######报警通知腾讯通号码：    04657
######当前报警时间戳：        20150505101314
=========================================================================================================================
######监控异常关键字：      "Exception"---数量=2

######$b is 17######
######错误信息：             3
 4
 java.lang.NullPointerException
 5
 6

=========================================================================================================================
######监控异常关键字：      "异常"---数量=1

######$b is 6######
######错误信息：             4444
 5555
 异常111
 a1
 a2