use Search::Dict; look *FILEHANDLE, $key, $dict, $fold;
$dict is true, the search is in dictionary order (ignoring
everything but word characters and whitespace). If
true, then case is ignored. The file must be sorted into the appropriate order,
using the -d and -f flags of UNIX
sort(1), or the equivalent command on non-UNIX
machines. Unpredictable results will otherwise ensue.