in reply to Negative look ahead
perl -ne 'chomp; !/^<title>/ ? print "<para>$_</para>\n" : print "$_\n +"' <input_file> [download]
See also perlrun, if you want to wrap ++graff's code into a 1-liner, using further options.
perl -ple '$_="<para>$_</para>" if !/^<title>/' [download]