Flight Rules are the hard-earned body of knowledge recorded in manuals 
that list, step-by-step, what to do if X occurs, and why. 
Essentially, they are extremely detailed, scenario-specific standard 
operating procedures.
— Chris Hadfield, An Astronaut's Guide to Life.

这里包含一些不适合作为博文出现的内容,主要是一些教程,比如如何安装某个库,如何使用某些软件,或者怎么处理某些bug。

简单地说:what to do if X occurs, and why.