chown

        # File.chown

(from ruby core)
---
    File.chown(owner_int, group_int, file_name, ...)  ->  integer

---

Changes the owner and group of the named file(s) to the given numeric
owner and group id's. Only a process with superuser privileges may
change the owner of a file. The current owner of a file may change the
file's group to any group to which the owner belongs. A `nil` or -1
owner or group id is ignored. Returns the number of files processed.

    File.chown(nil, 100, "testfile")


(from ruby core)
---
    file.chown(owner_int, group_int )   -> 0

---

Changes the owner and group of *file* to the given numeric owner and
group id's. Only a process with superuser privileges may change the
owner of a file. The current owner of a file may change the file's group
to any group to which the owner belongs. A `nil` or -1 owner or group id
is ignored. Follows symbolic links. See also File#lchown.

    File.new("testfile").chown(502, 1000)