world_readable?

        # File::Stat.world_readable?

(from ruby core)
### Implementation from Stat
---
    stat.world_readable? -> integer or nil

---

If *stat* is readable by others, returns an integer representing the
file permission bits of *stat*. Returns `nil` otherwise. The meaning of
the bits is platform dependent; on Unix systems, see `stat(2)`.

    m = File.stat("/etc/passwd").world_readable?  #=> 420
    sprintf("%o", m)                              #=> "644"