Sometimes, a comment will work just as well, without the overhead. Consider the following:
local $/; # INPUT_RECORD_SEPARATOR
As another option, in the documenation for 'English', there's a suggestion to use:
use English qw( -no_match_vars ) ;
to prevent the problems mentioned.
As for the 'evil variables', the following note is in 'perldoc perlre':
WARNING: Once Perl sees that you need one of $&, $`, or $' anywhere in
the program, it has to provide them for every pattern match. This may
substantially slow your program. Perl uses the same mechanism to produce $1, $2, etc, so you also pay a price for each pattern that contains capturing parentheses. (To avoid this cost while retaining the
grouping behaviour, use the extended regular expression "(?: ... )"
instead.) But if you never use $&, $` or $', then patterns without
capturing parentheses will not be penalized. So avoid $&, $', and $`
if you can, but if you can't (and some algorithms really appreciate
them), once you've used them once, use them at will, because you've
already paid the price. As of 5.005, $& is not so costly as the other