I see ichimunki has essentially said what follows, but let me just reiterate as this seems to be a FAQ.

Some of the mail sending modules will get you additional portability as they either implement their own SMTP server or rely upon a local or remote server. Mail::Sendmail is good for this, and some even have fallbacks down to a standard binary... (mailx, sendmail, etc.) You might also wish to consult this node.

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perl -pe "s/\b;([st])/'\1/mg"