html formatting in perl script

[charles]

i was given the following advice concerning a large amount of html being
used within a script:

It would be cleaner to use document templates instead of
embedding the page in your code. If you put it in your code,
it'd be clearer to use shell-style HERE documents than so many
multiline print statements.

could someone point me to a perldoc on HERE documents or doc templates?
otherwise my script has a large amount of print "...."; and print "<<tag"

thanks.