10.7 Ruby

Use it like in python by refering a global variable called '$r'.

[0x465D8810]> H ruby
Load done
==> Loading radare ruby api... ok
irb(main):001:0> $r
=> #<Radare:0xb703ad38>
irb(main):002:0> print $r.cmd("p8 3 @ esp")
01 00 00 
irb(main):003:0> 

Read radare.rb for more information about the API.