PP.pp(obj, STDERR)
$ ruby -r pp -e 'PP.pp [1,[*2..30],{a:4, b:5}], STDERR' > /dev/null
[1,
[2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13,
14,
15,
16,
17,
18,
19,
20,
21,
22,
23,
24,
25,
26,
27,
28,
29,
30],
{:a=>4, :b=>5}]