delete old branches on github

code.rb

#!/usr/bin/env ruby

require 'date'
require 'shellwords'

REMOTE = 'origin'
PROTECTED_BRANCHES = ['master']
YEARS_OLD = 2

def run_command(cmd)
  puts "  Running: #{cmd}" if ENV['DEBUG']
  `#{cmd}`.chomp
end

cutoff_date = (Date.today - (YEARS_OLD * 365)).to_s
puts "Checking for branches older than #{cutoff_date}"

run_command("git fetch #{REMOTE} --prune")

remote_branches = run_command("git branch -r --list '#{REMOTE}/*' --format='%(refname:short)'")
  .split("\n")
  .reject { |b| b.end_with?('HEAD') }

branches_to_delete = []
remote_branches.each do |branch|
  print '.'
  next if PROTECTED_BRANCHES.any? { |protected| branch.end_with?(protected) }

  last_commit_date = run_command("git log -1 --format=%ai #{Shellwords.escape(branch)}")
  date_only = last_commit_date.split(' ').first

  if date_only < cutoff_date
    branches_to_delete << { branch: branch, last_commit: date_only }
  end
rescue
  require 'irb'; binding.irb
end
puts

if branches_to_delete.any?
  puts "The following branches will be deleted:"
  branches_to_delete.each do |b|
    puts "  #{b[:branch]} (last commit: #{b[:last_commit]})"
  end
  puts
  puts "Press enter to delete the branches, control-c to quit"
  gets
  branches_to_delete.each do |b|
    run_command("git push #{REMOTE} --delete #{Shellwords.escape(b[:branch]).gsub("#{REMOTE}/", '')}")
  end
else
  puts "No branches older than #{YEARS_OLD} years found."
end