You can do it with RbReadline:
require 'rubygems'
require 'rb-readline'
module RbReadline
def self.prefill_prompt(str)
@rl_prefill = str
@rl_startup_hook = :rl_prefill_hook
end
def self.rl_prefill_hook
rl_insert_text @rl_prefill if @rl_prefill
@rl_startup_hook = nil
end
end
RbReadline.prefill_prompt("Previous query")
str = Readline.readline("Enter query: ", true)
puts "You entered: #{str}"