How do I drop to the IRB prompt from a running script?

Can I drop to an IRB prompt from a running Ruby script?

I want to run a script, but then have it give me an IRB prompt at a point in the program with the current state of the program, but not just by running rdebug and having a breakpoint.

you can use ruby-debug to get access to irb

require 'rubygems'
require 'ruby-debug'
x = 23
puts "welcome"
debugger
puts "end"

when program reaches debugger you will get access to irb.

Pry (an IRB alternative) also lets you do this, in fact it was designed from the ground up for exactly this use case :)

It's as easy as putting binding.pry at the point you want to start the session:

require 'pry'
x = 10
binding.pry

And inside the session:

pry(main)> puts x
=> 10

Check out the website: http://pry.github.com

Pry let's you:

drop into a session at any point in your code
view method source code
view method documentation (not using RI so you dont have to pre-generate it)
pop in and out of different contexts
syntax highlighting
gist integration
view and replay history
open editors to edit methods using edit obj.my_method syntax

A tonne more great and original features

apparently it requires a chunk of code to drop into irb.

Here's the link (seems to work well).

http://jameskilton.com/2009/04/02/embedding-irb-into-your-ruby-application


require 'irb'

module IRB
  def self.start_session(binding) # call this method to drop into irb
    unless @__initialized
      args = ARGV
      ARGV.replace(ARGV.dup)
      IRB.setup(nil)
      ARGV.replace(args)
      @__initialized = true
    end

    workspace = WorkSpace.new(binding)

    irb = Irb.new(workspace)

    @CONF[:IRB_RC].call(irb.context) if @CONF[:IRB_RC]
    @CONF[:MAIN_CONTEXT] = irb.context

    catch(:IRB_EXIT) do
      irb.eval_input
    end
  end
end

This feature is available from Ruby 2.4. You can just use binding.irb

E.g.

require 'irb'
a = 10
binding.irb
puts a

If you run above code, you will get irb console, so that you can inspect values of local variables and anything else that is in scope.

Source: http://blog.redpanthers.co/new-binding-irb-introduced-ruby-2-4/

Ruby commit: https://github.com/ruby/ruby/commit/493e48897421d176a8faf0f0820323d79ecdf94a

Just add this line to where you want the breakpoint:

require 'ruby-debug';debugger

but i suggest use pry instead of irb, which is super handy, insert the following line instead:

require 'pry'; binding.pry

I'm quite late to the game but if you're loading a script from within irb/pry already, a simple raise also works to pop you back out to the irb/pry prompt. I use this quite often when writing one off scripts within the rails console.

来源：https://stackoverflow.com/questions/1144560/how-do-i-drop-to-the-irb-prompt-from-a-running-script

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ruby

irb