Homebrew uninstall script

unbrew.rb

#!/usr/bin/env ruby
#
# CLI tool for locating and removing a Homebrew installation
# http://brew.sh/
#
# Copyright (C) 2014 Stephen C. Benner
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# Author: Stephen Benner
# https://github.com/SteveBenner
#
# Contributors:
# - @AaronKulick
# - @lloeki
# - @lewismc
#
# NOTE: This script has ONLY been tested and verified for the following operating systems:
# - macOS 10.9
#
# TODO/ROADMAP
# - v1.1: test deletion code, make sure it can ALWAYS remove 
# - v1.2: handle ENOENT errors (file not found)
# - v1.3: find and remove daemons installed by brew
# - v1.4: figure out why script can sometimes loop through multiple `locate_brew_path` runs
# - v1.5: fix git repo detection code so it doesn't break when brew is checked out but not installed
# - v1.6: improve script to work even without a Homebrew installation
#
require 'optparse'
require 'fileutils'
require 'open3'

$stdout.sync = true

# Default options
options = {
  :quiet     => false,
  :verbose   => true,
  :dry_run   => false,
  :force     => false,
  :find_path => false
}

optparser = OptionParser.new do |opts|
  opts.banner = 'Homebrew uninstaller' + $/
  opts.on('-q', '--quiet', 'Quiet mode - suppress output.') do |setting|
    options[:quiet]   = setting
    options[:verbose] = false
  end
  opts.on('-v', '--verbose', 'Verbose mode - print all operations.') { |setting| options[:verbose] = setting }
  opts.on('-d', '--dry', 'Dry run - print results, but perform no actual operations.') do |setting|
    options[:dry_run] = setting
  end
  opts.on('-f', '--force', 'Forces removal of files, bypassing prompt. USE WITH CAUTION!') do |setting|
    options[:force] = setting
  end
  opts.on('-p', '--find-path', 'Output homebrew location if found, then exit.') do |setting|
    options[:find_path] = setting
    options[:quiet]     = true
  end
  opts.on_tail('-h', '--help', '--usage', 'Display this message.') { puts opts; exit }
  opts.on_tail('--version', 'Display script version.') { puts opts.version; exit }
end
optparser.version = '1.0'
optparser.summary_width = 16
optparser.parse!

$quiet = options[:quiet] # provides access to option value within methods

# Files installed into the Homebrew repository
BREW_LOCAL_FILES = %w[
  .git
  Cellar
  Library/brew.rb
  Library/Homebrew
  Library/Aliases
  Library/Formula
  Library/Contributions
  Library/LinkedKegs
]
# Files that Homebrew installs into other system locations
BREW_SYSTEM_FILES = %W[
  #{ENV['HOME']}/Library/Caches/Homebrew
  #{ENV['HOME']}/Library/Logs/Homebrew
  /Library/Caches/Homebrew
]
$files = []

# This function runs given command in a sub-shell, expecting the output to be the
# path of a Homebrew installation. If given a block, it passes the shell output to
# the block for processing, using the return value of the block as the new path.
# Known Homebrew files are then scanned for and added to the file list. Then the
# directory is tested for a Homebrew installation, and the git index is added if
# a valid repo is found. The function won't run once a Homebrew installation is
# found, but it will accumulate untracked Homebrew files each invocation.
#
# @param  [String] cmd        A shell command to run
# @param  [String] error_msg  Message to print if command fails
#
def locate_brew_path(cmd, error_msg = 'check homebrew installation and PATH.')
  return if $brew_location # stop testing if we find a valid Homebrew installation
  puts "Searching for homewbrew installation using '#{cmd}'..." unless $quiet

  # Run given shell command along with any code passed-in via block
  path = `#{cmd}`.chomp
  path = yield(path) if block_given? # pass command output to your own fancy code block

  begin
    Dir.chdir(path) do
      # Search for known Homebrew files and folders, regardless of git presence
      $files += BREW_LOCAL_FILES.select { |file| File.exist? file }.map {|file| File.expand_path file }
      $files += Dir.glob('**/{man,bin}/**/brew*')
      # Test for Homebrew git repository (use popen3 so we can suppress git error output)
      repo_name = Open3.popen3('git remote -v') do |stdin, stdout, stderr|
        stderr.close
        stdout.read
      end
      if repo_name =~ /homebrew.git|Homebrew/
        $brew_location = path
      else
        return
      end
    end
  rescue StandardError # on normal errors, continue program
    return
  end
end

# Attempt to locate homebrew installation using a command and optional code block
# for processing the command results. Locating a valid path halts searching.
# TODO: Improve this code - refactor and add error handling
locate_brew_path 'brew --prefix'
locate_brew_path('which brew') { |output| File.expand_path('../..', output) }
locate_brew_path('command -v brew') { |output| File.expand_path('../..', output) }
locate_brew_path 'brew --prefix' do |output|
  output = output.split($/).first
  File.expand_path('../..', output)
end

# Found Homebrew installation
if $brew_location
  if options[:find_path]
    puts $brew_location
    exit
  end
  unless options[:quiet]
    puts "Homebrew found at: #{$brew_location}"
    begin # record kegs and taps for later output
      brewed = `brew list`
      tapped = `brew tap`
    rescue StandardError
    end
  end
  # Collect files indexed by git
  begin
    Dir.chdir($brew_location) do
      # Update file list (use popen3 so we can suppress git error output)
      Open3.popen3('git checkout master') { |stdin, stdout, stderr| stderr.close }
      $files += `git ls-files`.split.map {|file| File.expand_path file }
    end
  rescue StandardError => e
    puts e # Report any errors, but continue the script and collect any last files
  end
end

# Collect any files Homebrew may have installed throughout our system
$files += BREW_SYSTEM_FILES.select { |file| File.exist? file }

abort 'Failed to locate any homebrew files!' if $files.empty?

# DESTROY! DESTROY! DESTROY!
unless options[:force]
  print "Delete #{$files.count} files? "
  abort unless gets.rstrip =~ /y|yes/i
end

rm =
  if options[:dry_run]
    lambda { |entry| puts "deleting #{entry}" unless options[:quiet] }
  else
    lambda { |entry| FileUtils.rm_rf(entry, :verbose => options[:verbose]) }
  end

puts 'Deleting files...' unless options[:quiet]
$files.each(&rm)

# Print a list of formulae and kegs that were removed as part of the uninstall process
if brewed
  puts
  puts 'The following previously installed formulae were removed:'
  puts brewed
end
if tapped
  puts
  puts 'The following previously tapped kegs were removed:'
  puts tapped
end

I have vestigial homebrew files, but homebrew hasn't been installed for years, so I'm looking for an uninstaller that will clean up the files without having to reinstall homebrew. Unfortunately, like the official uninstaller, this doesn't work unless homebrew is installed.

2022 UPDATE:

I have added a list of fixes and improvements based on the last few years of feedback. Time to update the script! Thanks to the community for all the feedback and help testing this.

@lewismc, @lloeki these are great ideas and will be added as features

@Roboji, @claudia1204, @cmfrtblynmb728, @techartist, @binchuri

The output for all of your cases is similar, in that I can see a couple different possible bugs causing the same kind of issue for all of you.

There are several fixes I am going to implement, they are documented at the top of the script. It will take some time to test, but I’m confident I will soon know why it broke.

It would be helpful for those experiencing hangups using unbrew to kill it with CTL-C or similar, and report any errors that show up.