perl的expect和xml模組簡單使用

Expect.pm 模組：主要用來和另外一個server進行互動的，比如ftp，telnet等等。在寫一些監控腳步上，也會經常用到。
我所用到的方法很簡單，
spawn($command,@params),Forks and execs $command. Returns an Expect object upon success or undef if the fork was unsuccessful or the command could not be found. spawn() passes its parameters unchanged to Perls exec(), so look there for detailed semantics。起了一個新進程用來執行$command命令

new expect()->expect($timeout,$content),Given $timeout in seconds Expect will wait for $object's handle to produce one of the match_patterns, which are matched exactly by default. If you want a regexp match, prefix the pattern with '-re'.在$timeout內，期待出現包含$content的內容，預設是精確匹配，也可以使用Regex，expect($timeout,re=>'')

new expect()->send($string):Sends the given strings to the spawned command. 發送訊息

new expect()->debug(0|1|2): 列印debug 資訊，不同的數字表示不同的bug層級

new expect()->interact(),和使用者進行互動，把控制權轉交給使用者

new expect()->soft_close(), 軟關閉，直到$timeout時間到達，才關掉該進程

new expect()->hard_close(),硬關閉，立刻關閉該進程

new expect()->match(),returns the string matched by the last expect() call, undef if no string was matched.返回匹配的結果

new expect()->match_number(),exp_match_number() returns the number of the pattern matched by the last expect() call. Keep in mind that the first pattern in a list of patterns is 1, not 0. Returns undef if no pattern was matched.返回匹配的個數

例子：
#!/usr/bin/perl
use Expect;
use strict;

my $timeout = 20;
my $cmd = "telnet";
my $exp = Expect->spawn($cmd,"192.168.0.1") or die "Can't spawn $cmd!";
        $exp->expect($timeout,-re=>'[Ll]ogin:');
        $exp->send("test\r\n");
        $exp->expect($timeout,-re=>'[Pp]assword:');
        $exp->debug(1);
        $exp->send("test\r\n");
        $exp->expect($timeout,-re=>'Last login');
        $exp->send("ps -ef |grep java\r\n");
        $exp->expect($timeout,-re=>'java');
         print $exp->match_number();
        $exp->soft_close();

XML::Simple：xml與perl的介面，既可以從xml中讀取資料以hash或散列的形式存放，也可以通過perl將資料格式化寫到xml檔案裡。這裡主要介紹從xml中讀取結構化資料
XML::Simple->new()->XMLin(),從xml中讀取資料
XML::Simple->new()->XMLout(),往xml中寫資料
例子：
#!/usr/bin/perl -w
use strict;
use XML::Simple;
use Data::Dumper;
my $simple = XML::Simple->new();
my $data   = $simple->XMLin('pets.xml');
# DEBUG
print Dumper($data) . "\n";
# END
其中Dumper()用來查看放到記憶體中的資料結構
本例子pets.xml為
<?xml version='1.0'?>
<pets>
  <cat>
    <name>Madness</name>
    <dob>1 February 2004</dob>
    <price>150</price>
  </cat>
  <name>Maggie</name>
    <dob>12 October 2005</dob>
    <price>75</price>
    <owner>Rosie</owner>
  </dog>
  <cat>
    <name>Little</name>
    <dob>23 June 2006</dob>
    <price>25</price>
  </cat>
</pets>
dumpe()後的結果
$VAR1 = {
      'cat' => {
           'Little' => {
                   'dob' => '23 June 2006',
                   'price' => '25'
                 },
           'Madness' => {
                'dob' => '1 February 2004',
                'price' => '150'
                  }
         },
      'dog' => {
           'owner' => 'Rosie',
           'dob' => '12 October 2005',
           'name' => 'Maggie',
           'price' => '75'
         }
    };
我們可以通過@{$VAR1{cat}}[0]->{dob}形式來訪問hash內容，該值為"23 June 2006"

關於更多的xml和perl介面的文章，可以參考此連結