comment on

If you're not fixed on LWP::Simple, here's an example with Mojolicious:

use Mojo::UserAgent;
my $url = "http://de.arxiv.org/pdf/1106.3541"
print Mojo::UserAgent->new->head($url)->res->headers->content_type;
[download]

This prints application/pdf, indicating that document returned from this URL is a PDF file.

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