I'm pretty sure I've done this before but don't remember. If you're doing the calling one thing to consider is using the filename as the filehandle in the form of a scalar.

$filename = '/etc/hosts';
open($filename, $filename);
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It is left as an excercies for the reader to worry about potential security pitfalls (Hint: not specifying the mode).

--
perl -p -e "s/(?:\w);([st])/'\$1/mg"