如何正确阅读Shell语法?

How to correctly and precisely read the Shell Grammar hosted at https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_10_02, especially that is written after "The grammar symbols"? I'm not saying i can't get it at all, i understand it roughly, but i think there should be something like a "standard for standard" on how to read and write Shell Grammar properly..

评论