irbr - record irb history to the file of your choice

irbr.rb

#!/usr/bin/env ruby

# irbr (short for "IRB Recorder")
#
# Starts an IRB session and appends your history to the specified file
# or "scratch.rb" by default
#
# USAGE irbr.rb output.rb

require "irb"

file = ARGV.first || "scratch.rb"

IRB.conf[:HISTORY_FILE] = file
IRB.conf[:SAVE_HISTORY] = 10_000

IRB.start