出现（E）世界优化器（EWO）

Ewo is a tool written in Python for the Gentoo GNU/Linux distribution to optimize the recompilation of the whole system, all installed packages. Usually one can simply use emerge -e world and emerge --resume when something bad happens, but sometimes you need to run another emerge process to solve a problem and this alter the desired emerge --resume behavior. Ewo solves this issue and it can be used in general to compile all the packages that have not been updated or replaced after a specific date (CFLAGS, LDFLAGS change, compiler upgrade and so on). Using a config file named package.skip the user can avoid useless packages reinstallation, like large binary packages for example. Take a look at ewo --help before use it or read BasicHelp