为什么我会得到“一个”呢；“没有找到的路径”；XML:：XPath中的错误？

我正在尝试运行我创建的Perl文件

use XML::XPath;
use XML::XPath::XMLParser;

# create an object to parse the file and field XPath queries
my $xpath = XML::XPath->new( filename => shift @ARGV );

# apply the path from the command line and get back a list matches
my $nodeset = $xpath->find( shift @ARGV );

# print each node in the list
foreach my $node ( $nodeset->get_nodelist ) {
  print XML::XPath::XMLParser::as_string( $node ) . "\n";
}

当我运行

perlxmlfile.pl

时，我得到了这个错误

"No path to find at /usr/lib/per5/site_perl/5.8.8/XML/XPath.pm line 65"

它期待着

perl xmlfile.pl file.xml /some/xpath

---

程序需要命令行参数，首先是文件名，然后是XPath表达式。这就是暗示。尝试：

perl xmlfile.pl ex07_xpathdata.xml '//item'