if you want to grep on whole fields, you might be able to use a hash.

Just be sure to always lowercase the keys to be case insensitive.

kind of:

$hash{lc($key)}=$line; # for file to search

print @hash{@to_find}; # @to_find from grep-file
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If possible I'd prefer this over the hassle to avoid regex-metacharacters.

YMMV! =)