One simply escapes it, this works even if it is part of code to be executed: 
$_ = '22C';
s/(\d+)C/($1*9\/5)+32 . "F"/ge;
print;

[download]
produces 71.6F. Dedalus.

In reply to Re: regexp - how to embed a "/" within the executable part of the regexp when using /e by Dedalus
in thread regexp - how to embed a "/" within the executable part of the regexp when using /e by princepawn

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