The quickest thing for you to do is to comment out the opening of the file and closing, ie: these lines

open(HTMLFILE,">pingresults.html") || die "Couldn't open pingresults";
close (HTMLFILE);
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Place a # mark in front of it. and instead of print HTMLFILE "$HTML\n"; just say print "$HTML\n";, or if you want to be explicit about it, replace HTMLFILE with STDOUT in the print statement. So,

open(HTMLFILE, ">pingresults.html") || die "Couldn't open pingresults\
+n";
print HTMLFILE "$HTML\n";
close (HTMLFILE);
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becomes

# open(HTMLFILE, ">pingresults.html") || die "Couldn't open pingresult
+s\n";
print STDOUT "$HTML\n";
# close (HTMLFILE);
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HTH