perl脚本中运行含有管道的系统命令时，不能将异常输出重定向到文本

perl脚本中运行含有管道的系统命令时，不能将错误输出重定向到文本
我有一段perl脚本如下：
while(1)
  {
  my @i = ();
  my $command = <FH>;
  if(not defined ($command))
  {
  last;
  }
  chomp($command);
  print RESULT "$command\n";
  @i = `$command 2>&1`;
  print RESULT @i;
 }
FH和RESULT 都是文件句柄，
结果文件：
cat /etc/opasswd1
cat: /etc/opasswd1: No such file or directory
cat /etc/opasswd1 | grep -v "^#"

好像命令行中不加管道就能将标准输出打印到文本中，加了管道就不能输出到文本中，但是会打到屏幕上，
请高手帮忙看下，谢谢！



------解决方案--------------------
Because backticks do not affect standard error, use shell file descriptor syntax (assuming the shell supports this) if you care to address this. To capture a command's STDERR and STDOUT together:

$output = `cmd 2>&1`;

To capture a command's STDOUT but discard its STDERR:

$output = `cmd 2>/dev/null`;

To capture a command's STDERR but discard its STDOUT (ordering is important here):

$output = `cmd 2>&1 1>/dev/null`;

To exchange a command's STDOUT and STDERR in order to capture the STDERR but leave its STDOUT to come out the old STDERR:

$output = `cmd 3>&1 1>&2 2>&3 3>&-`;