Shell Programming and Scripting

So, I've just started learning Perl, and I've decided to read up on some modules. I encountered WWW::Mechanize, which interests me, so I decided to try out a couple of basic tutorials. One of them is found here. I tried what seems a very basic case:

Code:

#!/usr/bin/perl
use WWW::Mechanize;
$url = 'http://www.google.com';
$m->get($url);
$link = $m->find_link(text => 'Advanced Search');
print "The Google advanced search URL is:  $link->url()\n";

Strict pragma is not being used, so this should be fairly forgiving. The error message I get is:

Code:

Can't call method "get" on an undefined value at ./googlemech.pl line 4.

So, it seems reasonable to make sure that the value $url is actually being properly assigned. I commented out the last 3 lines and added this after the $m assignment lines:

Code:

print "$url\n"

It printed "http://www.google.com" (without quotes) properly. To back this up, I explicitly stated "http://www.google.com" in the "get" portion, and got the same error. So, it appears that the problem is not with variable assignment. That suggests that perhaps the WWW::Mechanize module isn't installed. So, I did "perldoc perllocal" and got:

Code:

Fri Feb 12 13:29:52 2010: "Module" WWW::Mechanize

with the usual accompanying information. I did the installation through CPAN about an hour ago. It appears to be installed and available, and yet the script fails. Do I have to do anything to "initialize" the module, so to speak? If not, what in the world might be going wrong with this? Many thanks in advance.

The error message is pretty telling. Line 4 is

Code:

$m->get($url);

, and somewhere in there is an undefined value. You've established that it ain't $url, so what's left?

The problem with the second example in the given tutorial is that it isn't runnable, unless you apply some common sense and re-use a line from the first example:

Code:

my $m = WWW::Mechanize->new();

Include that line before you call any methods on $m (which is undefined otherwise), and you should be fine.

Also, reading through perldoc WWW::Mechanize::Examples might give a hint or two.