I guess you mean something like the below. Obviously add your own error handling but this should point you in the right direction I would hope.

#!/usr/bin/env perl 
use strict;
use warnings;
use LWP::UserAgent;
use Digest::SHA 'sha256_hex';

my $response = LWP::UserAgent->new->get ('https://www.perlmonks.org/?n
+ode_id=11118766');
my $digest  = sha256_hex ($response->decoded_content);
print "The digest is '$digest'\n";
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