Hi and welcome ron800, i'm not an expert of XML but when i need to get rid of such a shaggy thing i definetively use XML::Twig. It can do many many many things for you.

For example XML::Twig has an option (never seen before your question..) LoadDTD and is not to kill bugs on the twig.. ;=)

Is used to load DTD (internal OR external.. be aware!).
you can use also a DTDHandler to handle the DTD.
See the docs about XML::Twig methods (DTDHandler ) and also the dedicate section.

After reading the section you (me too..) discover that DTDHanlder receive two params: the twig itself and the DTD. So you can check for $_[1] ie the second element of the array passed to a subroutine. 
cat with_dtd.xml
<?xml version="1.0"?>
<!DOCTYPE p [
 <!ELEMENT p ANY>
]>
<p>Hello world!</p>

perl -MXML::Twig -e "$twig= new XML::Twig(LoadDTD=>1,DTDHandler=>sub{p
+rint qq(FOUND\n) if $_[1]});$twig->parsefile($ARGV[0])" with_dtd.xml

#output..
FOUND


cat withOUT_dtd.xml
<?xml version="1.0"?>
<p>Hello world!</p>

perl -MXML::Twig -e "my $twig= new XML::Twig(LoadDTD=>1,DTDHandler=>su
+b{print qq(FOUND\n) if $_[1]});$twig->parsefile($ARGV[0])" withOUT_dt
+d.xml

#output..

[download]

HtH
L*
There are no rules, there are no thumbs..
Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.

In reply to Re: Quick check for XML DTD or Schema.. XML::Twig solution by Discipulus
in thread Quick check for XML DTD or Schema by ron800

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