Hello Rubyists, VVSiz led me to this one. On 1.8.6: >> "A" =~ /[^a]/i => nil On trunk: >> "A" =~ /[^a]/i => 0 The 1.8.6 behavior seems correct, though. Every alternative distribution which has also followed Oniguruma suffers from this bug. Evan -- Evan Weaver Cloudburst, LLC