Struct Example 

pub struct Example {
    pub cmd: &'static str,
    pub exit: i32,
    pub says: &'static str,
}

One example: a shell line and what it does.

Fields

cmd: &'static str

What to type. The first trg … in it, up to the first unquoted |, ;, &, >, <, ) or newline, is what the test runs; anything around it is shell the reader can copy as it stands.

exit: i32

The exit code that trg part gives against the tree in FILES.

says: &'static str

Plain prose, wrapped when printed.