function fileExists(file)
   t, msg = io.open(file, "r")
   if not t then return false end
   return true
end

function string.endsWith(String,End)
   return End=='' or string.sub(String,-string.len(End))==End
end

function fixFileName(file)
   return string.gsub(file, "[\\/^*<>|?:\"]", "_")
end