Expect.pm 模块：主要用来和另外一个server进行交互的，比如ftp，telnet等等。在写一些监控脚步上，也会经常用到。
我所用到的方法很简单，
spawn($command,@params),Forks and execs $command. Returns an Expect object upon success or undef if the fork was unsuccessful or the command could not be found. spawn() passes its parameters unchanged to Perls exec(), so look there for detailed semantics。起了一个新进程用来执行$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内，期待出现包含$content的内容，默认是精确匹配，也可以使用正则表达式，expect($timeout,re=>'')
new expect()->send($string):Sends the given strings to the spawned command. 发送消息
new expect()->debug(0|1|2): 打印debug 信息，不同的数字表示不同的bug级别
new expect()->interact(),和用户进行交互，把控制权转交给用户
new expect()->soft_close(), 软关闭，直到$timeout时间到达，才关掉该进程
new expect()->hard_close(),硬关闭，立刻关闭该进程
new expect()->match(),returns the string matched by the last expect() call, undef if no string was matched.返回匹配的结果
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.返回匹配的个数
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与perl的接口，既可以从xml中读取数据以hash或散列的形式存放，也可以通过perl将数据格式化写到xml文件里。这里主要介绍从xml中读取结构化数据
XML::Simple->new()->XMLin(),从xml中读取数据
XML::Simple->new()->XMLout(),往xml中写数据
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()用来查看放到内存中的数据结构
本例子pets.xml为
<?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()后的结果
$VAR1 = {
'cat' => {
'Little' => {
'dob' => '23 June 2006',
'price' => '25'
},
'Madness' => {
'dob' => '1 February 2004',
'price' => '150'
}
},
'dog' => {
'owner' => 'Rosie',
'dob' => '12 October 2005',
'name' => 'Maggie',
'price' => '75'
}
};
我们可以通过@{$VAR1{cat}}[0]->{dob}形式来访问hash内容，该值为"23 June 2006"
关于更多的xml和perl接口的文章，可以参考此链接