This is my current irbrc file which contains lots of helpful things.

.irbrc

require 'irb/completion'
require 'rubygems'

ActiveRecord::Base.logger.level = 1 if defined?(ActiveRecord)
IRB.conf[:SAVE_HISTORY] = 1000
# IRB.conf[:ECHO] = false

# Overriding Object class
class Object
  # Easily print methods local to an object's class
  def lm
    (methods - Object.instance_methods).sort
  end

  # look up source location of a method
  def sl(method_name)
    self.method(method_name).source_location rescue "#{method_name} not found"
  end

  # open particular method in vs code
  def ocode(method_name)
    file, line = self.sl(method_name)
    if file && line
      `code -g '#{file}:#{line}'`
    else
      "'#{method_name}' not found :(Try #{self.name}.lm to see available methods"
    end
  end

  # display method source in rails console
  def ds(method_name)
    self.method(method_name).source.display
  end

  # open json object in VS Code Editor
  def oo
    tempfile = File.join(Rails.root.join('tmp'), SecureRandom.hex)
    File.open(tempfile,'w') {|f| f << self.as_json}
    system("#{'code'||'nano'} #{tempfile}")
    sleep(1)
    File.delete( tempfile )
  end
end

# history command
def hist(count = 0)
  # Get history into an array
  history_array = Readline::HISTORY.to_a

  # if count is > 0 we'll use it.
  # otherwise set it to 0
  count = count > 0 ? count : 0

  if count > 0
    from = history_array.length - count
    history_array = history_array[from..-1]
  end

  print history_array.join("\n")
end

# copy a string to the clipboard
def cp(string)
  `echo "#{string}" | pbcopy`
  puts "copied in clipboard"
end

# Get current logged-in user for selldo
def getcu
  begin
    last_lines = `tail -n 500 'log/development.log'`;nil
    User.find(last_lines[(last_lines.rindex("logged_in_user:") + 15), 24])
  rescue Exception => e
    puts "Error in getting user - #{e.message}"
  end
end

# Get client for currently loggedin user
def getc
  begin
    getcu.client
  rescue Exception => e
    puts "Error in getting client - #{e.message}"
  end
end

# Get latest record for particular class #Mongo
def gl(cname)
  begin
    eval("#{cname.to_s}").desc(:created_at).first
  rescue => e
    puts "Error in get latest record - #{e.message}"
  end
end

# Create a lead if current application is CRM
def clead(usr = getcu)
  if Rails.application.class.parent_name == 'Crm' && usr && ['pre_sales','sales'].include?(usr.role)
    begin
      ::FactoryGirl.create(:lead, :with_organic_campaign, :with_primary_email ,client: usr.client, sales: usr)
    rescue => e
      puts "Error in creating lead - #{e.message}"
    end
  else
    puts "not able to create lead for admin/manager/cusrom login"
  end
end

# reloads the irb console can be useful for debugging .irbrc
def reload_irb
  load File.expand_path("~/.irbrc")
  # will reload rails env if you are running ./script/console
  reload! if @script_console_running
  puts "Console Reloaded!"
end

# opens irbrc in vscode
def edit_irb
  `code ~/.irbrc` if system("code")
end

def bm
  # From http://blog.evanweaver.com/articles/2006/12/13/benchmark/
  # Call benchmark { } with any block and you get the wallclock runtime
  # as well as a percent change + or - from the last run
  cur = Time.now
  result = yield
  print "#{cur = Time.now - cur} seconds"
  puts " (#{(cur / $last_benchmark * 100).to_i - 100}% change)" rescue puts ""
  $last_benchmark = cur
  result
end

# exit using `q`
alias q exit

# all available methods explaination
def ll
  puts "obj.sl ------> source location"
  puts "obj.ocode ---> open method in vs code"
  puts "obj.ds ------> display method source in rails console"
  puts "obj.oo ------> open object json in vs code"
  puts "hist(n) -----> command history"
  puts "cp(str) -----> copy string in clipboard"
  puts "getcu -------> current logged-in user in sell.do"
  puts "getc --------> current logged-in user's client in sell.do"
  puts "gl(:Class) --> Get last inserted record in Class"
  puts "clead(u) ----> Create a lead for sales/pre-sales user passed as an argument"
  puts "bm(block) ---> benchmarking for block passed as an argument"
  puts "reload_irb --> reloading console and irbrc"
  puts "edit_irb ----> edit irbrc in vs code"
  puts "q -----------> exit from console"
end