Maybe your problem is that you are using backticks to execute wget. You need only system or backticks. If you need to save something in a different directory you should use the -P option of wget:

system 'wget -P /usr/tmp http://192.168.0.1/abc'
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If you want to use only Perl, then look at LWP::Simple; a simple example:

use LWP::Simple;

mirror('http://192.168.0.1/abc', '/usr/tmp/abc');
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Ciao, Valerio