Other monks have already said everything I would say about why one should use Perl, but there's one thing I haven't seen much of a response to. You mention PHP "seem[ing]" like it is "now ... more popular than perl." My only response to that is, "Who cares?!?" I know I sure don't. Popularity only matters insomuch that there is a healthy community around a language. Perl still has a healthy community -- even in the "arena of CGI." (I put quotes around this because most PHP is probably not actually using CGI, and most sane Perl web apps shouldn't either.) This all leads me to my hyper-obvious conclusion: popularity sucks. Use what works.
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