字谜

Definition: “A segment of an awk program, that specifies how to process single input records. A ____ consists of a pattern and an action. awk reads an input record; then, for each ____, if the input record satisfies the ____'s pattern, awk executes the ____'s action. Otherwise, the ____ does nothing for that input record.”

第一个字母: R

请回答  

这个单词是什么?

"智商" 0