print reverse <>; # line tac, last line first
undef $/; # for efficiency of <>
print scalar reverse <>; # byte tac, last line tsrif
This operator is also handy for inverting a hash, although there are some caveats. If a value is duplicated in the original hash, only one of those can be represented as a key in the inverted hash. Also, this has to unwind one hash and build a whole new one, which may take some time on a large hash.
%by_name = reverse %by_address; # Invert the hash