Golf? -p and $_= save you one space over -n and say:
perl -aplF"/\./" -E"$_=join q{.},reverse@F" zones.txt
and a manual split takes less than -F (assuming you don't get flags for free):
perl -lpE"$_=join q{.},reverse split/\./" zones.txt
Using $, in place of join saves you 2, except then you lose $_=
perl -lnE"$,=q{.};say reverse split/\./" zones.txt
but you still win w/ a regex:
perl -pE"s/(.+)\.(.+)\.(.+)/$3.$2.$1/" zones.txt
and to me, that one seems a whole lot more obvious than the other offerings.
#11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.
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