diff --git a/.github/workflows/rspec.yml b/.github/workflows/rspec.yml
deleted file mode 100644
index 2ddcae6..0000000
--- a/.github/workflows/rspec.yml
+++ /dev/null
@@ -1,40 +0,0 @@
-name: "RSpec"
-
-on:
-  push:
-    branches: [ main ]
-  pull_request:
-    branches: [ main ]
-
-jobs:
-  rspec:
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-          ruby:
-              - '2.7'
-              - '3.0'
-
-    steps:
-    - name: Checkout repository
-      uses: actions/checkout@v3
-
-    - name: Set up Ruby
-      uses: ruby/setup-ruby@f20f1eae726df008313d2e0d78c5e602562a1bcf
-      with:
-        ruby-version: ${{ matrix.ruby }}
-
-    - name: Install dependencies
-      run: bundle install --with=ci
-
-    - name: Run tests
-      run: bundle exec rake spec_github
-
-    - name: Publish Test Report
-      uses: mikepenz/action-junit-report@41a3188dde10229782fd78cd72fc574884dd7686
-      if: always() # always run even if the previous step fails
-      with:
-        report_paths: rspec.xml
-        check_name: Rspec for Ruby ${{ matrix.ruby }}
-        fail_on_failure: true
diff --git a/.github/workflows/rubocop.yml b/.github/workflows/rubocop.yml
deleted file mode 100644
index 732cf2b..0000000
--- a/.github/workflows/rubocop.yml
+++ /dev/null
@@ -1,44 +0,0 @@
-# This workflow uses actions that are not certified by GitHub.
-# They are provided by a third-party and are governed by
-# separate terms of service, privacy policy, and support
-# documentation.
-
-# pulled from repo
-name: "Rubocop"
-
-on:
-  push:
-    branches: [ main ]
-  pull_request:
-    # The branches below must be a subset of the branches above
-    branches: [ main ]
-
-jobs:
-  rubocop:
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-
-    steps:
-    - name: Checkout repository
-      uses: actions/checkout@v3
-
-    - name: Set up Ruby
-      uses: ruby/setup-ruby@f20f1eae726df008313d2e0d78c5e602562a1bcf
-      with:
-        ruby-version: 2.7
-
-    - name: Install dependencies
-      run: bundle install --with=ci
-
-    - name: Rubocop run
-      run: |
-        bash -c "
-          bundle exec rake lint_github
-          [[ $? -ne 2 ]]
-        "
-
-    - name: Upload Sarif output
-      uses: github/codeql-action/upload-sarif@v2
-      with:
-        sarif_file: rubocop.sarif
diff --git a/.gitignore b/.gitignore
deleted file mode 100644
index e54ca87..0000000
--- a/.gitignore
+++ /dev/null
@@ -1,4 +0,0 @@
-vendor/
-.bundle/
-pkg/
-rspec.xml
diff --git a/.rubocop.yml b/.rubocop.yml
deleted file mode 100644
index f3d5561..0000000
--- a/.rubocop.yml
+++ /dev/null
@@ -1,16 +0,0 @@
-require:
-    - rubocop-rake
-
-AllCops:
-    NewCops: enable
-    TargetRubyVersion: 2.7
-    Exclude:
-        - "vendor/**/*"
-
-Metrics/MethodLength:
-    Max: 15
-
-Metrics/BlockLength:
-    Exclude:
-        - bin/git-format-staged  # Long block for option parser is ok
-        - spec/**/*.rb
diff --git a/.ruby-version b/.ruby-version
deleted file mode 100644
index a603bb5..0000000
--- a/.ruby-version
+++ /dev/null
@@ -1 +0,0 @@
-2.7.5
diff --git a/.vscode/settings.json b/.vscode/settings.json
deleted file mode 100644
index ff30c44..0000000
--- a/.vscode/settings.json
+++ /dev/null
@@ -1,3 +0,0 @@
-{
-    "editor.tabSize": 2
-}
\ No newline at end of file
diff --git a/Gemfile b/Gemfile
deleted file mode 100644
index c57d2a7..0000000
--- a/Gemfile
+++ /dev/null
@@ -1,16 +0,0 @@
-# frozen_string_literal: true
-
-source 'http://rubygems.org'
-
-gemspec
-
-group :ci do
-  gem 'code-scanning-rubocop'
-  gem 'rspec_junit_formatter'
-end
-
-
-gem 'rake', '~> 13.0'
-gem 'rspec'
-gem 'rubocop', '~> 1.29'
-gem 'rubocop-rake', '~> 0.6'
diff --git a/Gemfile.lock b/Gemfile.lock
deleted file mode 100644
index 9344382..0000000
--- a/Gemfile.lock
+++ /dev/null
@@ -1,72 +0,0 @@
-PATH
-  remote: .
-  specs:
-    format-staged (0.1.2)
-      colorize
-
-GEM
-  remote: http://rubygems.org/
-  specs:
-    ast (2.4.2)
-    code-scanning-rubocop (0.6.1)
-      rubocop (~> 1.0)
-    colorize (1.1.0)
-    diff-lcs (1.5.1)
-    json (2.7.2)
-    language_server-protocol (3.17.0.3)
-    parallel (1.25.1)
-    parser (3.3.4.0)
-      ast (~> 2.4.1)
-      racc
-    racc (1.8.1)
-    rainbow (3.1.1)
-    rake (13.2.1)
-    regexp_parser (2.9.2)
-    rexml (3.3.9)
-    rspec (3.13.0)
-      rspec-core (~> 3.13.0)
-      rspec-expectations (~> 3.13.0)
-      rspec-mocks (~> 3.13.0)
-    rspec-core (3.13.0)
-      rspec-support (~> 3.13.0)
-    rspec-expectations (3.13.1)
-      diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.13.0)
-    rspec-mocks (3.13.1)
-      diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.13.0)
-    rspec-support (3.13.1)
-    rspec_junit_formatter (0.6.0)
-      rspec-core (>= 2, < 4, != 2.12.0)
-    rubocop (1.65.1)
-      json (~> 2.3)
-      language_server-protocol (>= 3.17.0)
-      parallel (~> 1.10)
-      parser (>= 3.3.0.2)
-      rainbow (>= 2.2.2, < 4.0)
-      regexp_parser (>= 2.4, < 3.0)
-      rexml (>= 3.2.5, < 4.0)
-      rubocop-ast (>= 1.31.1, < 2.0)
-      ruby-progressbar (~> 1.7)
-      unicode-display_width (>= 2.4.0, < 3.0)
-    rubocop-ast (1.31.3)
-      parser (>= 3.3.1.0)
-    rubocop-rake (0.6.0)
-      rubocop (~> 1.0)
-    ruby-progressbar (1.13.0)
-    unicode-display_width (2.5.0)
-
-PLATFORMS
-  ruby
-
-DEPENDENCIES
-  code-scanning-rubocop
-  format-staged!
-  rake (~> 13.0)
-  rspec
-  rspec_junit_formatter
-  rubocop (~> 1.29)
-  rubocop-rake (~> 0.6)
-
-BUNDLED WITH
-   2.1.4
diff --git a/README.md b/README.md
index bcf923c..6bfa56d 100644
--- a/README.md
+++ b/README.md
@@ -1,109 +1,3 @@
 # git-format-staged
 
-Port of [hallettj/git-format-staged](https://github.com/hallettj/git-format-staged) 
-to Ruby.
-
-Consider a project where you want all code formatted consistently. So you use
-a formatter and/or linter. (For example [SwiftFormat][]) You want to make sure 
-that everyone working on the project runs the formatter, add a git pre-commit
-hook to run it. The naive way to write that hook would be to:
-
-- get a list of staged files
-- run the formatter on those files
-- run `git add` to stage the results of formatting
-
-The problem with that solution is it forces you to commit entire files. At
-worst this will lead to contributors to unwittingly committing changes. At
-best it disrupts workflow for contributors who use `git add -p`.
-
-git-format-staged tackles this problem by running the formatter on the staged
-version of the file. Staging changes to a file actually produces a new file
-that exists in the git object database. git-format-staged uses some git
-plumbing commands to send content from that file to your formatter. The command
-replaces file content in the git index. The process bypasses the working tree,
-so any unstaged changes are ignored by the formatter, and remain unstaged.
-
-After formatting a staged file git-format-staged computes a patch which it
-attempts to apply to the working tree file to keep the working tree in sync
-with staged changes. If patching fails you will see a warning message. The
-version of the file that is committed will be formatted properly - the warning
-just means that working tree copy of the file has been left unformatted. The
-patch step can be disabled with the `--no-update-working-tree` option.
-
-[SwiftFormat]: https://github.com/nicklockwood/SwiftFormat
-
-## How to install
-
-Requires Ruby 2.7 or newer. Tests run on 2.7 and 3.0.
-
-Install as a development dependency in a project that uses bundle to manage
-Ruby dependencies:
-
-    $ bundle add format-staged
-
-Or install globally:
-
-    $ gem install format-staged
-
-## How to use
-
-For detailed information run:
-
-    $ [bundle exec] git-format-staged --help
-
-The command expects a shell command to run a formatter, and one or more file
-patterns to identify which files should be formatted. For example:
-
-    $ git-format-staged --formatter 'prettier --stdin-filepath "{}"' '*.js'
-
-That will format all `.js` files using `prettier`.
-
-The formatter command must read file content from `stdin`, and output formatted
-content to `stdout`.
-
-Patterns are evaluated from left-to-right: if a file matches multiple patterns
-the right-most pattern determines whether the file is included or excluded.
-
-git-format-staged never operates on files that are excluded from version
-control. So it is not necessary to explicitly exclude stuff like
-`vendor/`.
-
-The formatter command may include a placeholder, `{}`, which will be replaced
-with the path of the file that is being formatted. This is useful if your
-formatter needs to know the file extension to determine how to format or to
-lint each file. For example:
-
-    $ git-format-staged -f 'prettier --stdin-filepath "{}"' '*.js' '*.css'
-
-Do not attempt to read or write to `{}` in your formatter command! The
-placeholder exists only for referencing the file name and path.
-
-### Check staged changes with a linter without formatting
-
-Perhaps you do not want to reformat files automatically; but you do want to
-prevent files from being committed if they do not conform to style rules. You
-can use git-format-staged with the `--no-write` option, and supply a lint
-command instead of a format command. Here is an example using ESLint:
-
-    $ git-format-staged --no-write -f 'eslint --stdin --stdin-filename "{}" >&2' 'src/*.js'
-
-If this command is run in a pre-commit hook, and the lint command fails the
-commit will be aborted and error messages will be displayed. The lint command
-must read file content via `stdin`. Anything that the lint command outputs to
-`stdout` will be ignored. In the example above `eslint` is given the `--stdin`
-option to tell it to read content from `stdin` instead of reading files from
-disk, and messages from `eslint` are redirected to `stderr` (using the `>&2`
-notation) so that you can see them.
-
-### Why the Ruby port if there already is a fine Python implementation?
-
-I don’t like Python ;)
-
-But jokes aside, I am already setting up a Ruby environment (using [rbenv][]) for my 
-projects to run [cocoapods][] and [fastlane][] and our git hooks. By using this port
-we don’t need to ensure to have python available as well.
-
-
-[rbenv]: https://github.com/rbenv/rbenv/
-[cocoapods]: https://cocoapods.org/
-[fastlane]: https://fastlane.tools/
+Port of [hallettj/git-format-staged](https://github.com/hallettj/git-format-staged) to Ruby.
diff --git a/Rakefile b/Rakefile
deleted file mode 100644
index f0ec11c..0000000
--- a/Rakefile
+++ /dev/null
@@ -1,30 +0,0 @@
-# frozen_string_literal: true
-
-require 'bundler/gem_tasks'
-
-begin
-  Bundler.setup(:default, :development)
-rescue Bundler::BundlerError => e
-  warn e.message
-  warn 'Run `bundle install` to install missing gems'
-  exit e.status_code
-end
-
-require 'rubocop/rake_task'
-
-desc 'Run RuboCop'
-RuboCop::RakeTask.new(:lint)
-
-desc 'Run RuboCop for GitHub'
-RuboCop::RakeTask.new(:lint_github) do |t|
-  t.requires << 'code_scanning'
-  t.formatters << 'CodeScanning::SarifFormatter'
-  t.options << '-o' << 'rubocop.sarif'
-end
-
-require 'rspec/core/rake_task'
-RSpec::Core::RakeTask.new(:spec)
-
-RSpec::Core::RakeTask.new(:spec_github) do |t|
-  t.rspec_opts = '--format RspecJunitFormatter --out rspec.xml'
-end
diff --git a/bin/git-format-staged b/bin/git-format-staged
index 2111bcc..7a35a41 100755
--- a/bin/git-format-staged
+++ b/bin/git-format-staged
@@ -1,82 +1,54 @@
 #!/usr/bin/env ruby
-# frozen_string_literal: true
-
-require 'format_staged'
+require 'format-staged'
 require 'optparse'
 
 parameters = {
-  update: true,
-  write: true,
-  verbose: false
+  :update => true,
+  :write => true,
+  :verbose => false,
 }
 
 parser = OptionParser.new do |opt|
   opt.banner = "Usage: #{opt.program_name} [options] [patterns]"
-  opt.separator ''
-  opt.on('-f', '--formatter COMMAND',
-         <<~DOC
-           Shell command to format files, will run once per file. Occurrences of the placeholder `{}` will \
-           be replaced with a path to the file being formatted. \
-           (Example: "prettier --stdin-filepath '{}'")
-         DOC
-  ) do |o|
+  opt.separator ""
+  opt.on('-f', '--formatter COMMAND', 'Shell command to format files, will run once per file. Occurrences of the placeholder `{}` will be replaced with a path to the file being formatted. (Example: "prettier --stdin-filepath \'{}\'")') do |o|
     parameters[:formatter] = o
   end
-
-  opt.on('--[no-]update-working-tree',
-         <<~DOC
-           By default formatting changes made to staged file content will also be applied to working tree \
-           files via a patch. This option disables that behavior, leaving working tree files untouched.#{' '}
-         DOC
-        ) do |value|
+  
+  opt.on('--[no-]update-working-tree', 'By default formatting changes made to staged file content will also be applied to working tree files via a patch. This option disables that behavior, leaving working tree files untouched.') do |value|
     parameters[:update] = value
   end
-
-  opt.on('--[no-]write',
-         <<~DOC
-           "Prevents #{opt.program_name} from modifying staged or working tree files. You can use this option \
-           to check staged changes with a linter instead of formatting. With this option stdout from the \
-           formatter command is ignored."
-         DOC
-        ) do |value|
+  
+  opt.on('--[no-]write', "Prevents #{opt.program_name} from modifying staged or working tree files. You can use this option to check staged changes with a linter instead of formatting. With this option stdout from the formatter command is ignored.") do |value|
     parameters[:write] = value
   end
-
-  opt.on('-v', '--[no-]verbose', 'Shows commands being run') do |value|
+  
+  opt.on("-v", "--[no-]verbose", 'Shows commands being run') do |value| 
     parameters[:verbose] = value
   end
 
-  opt.separator ''
-
+  opt.separator ""
+  
   opt.on_tail('-h', '--help', 'Prints this help') do
     puts opt
     exit
   end
-
-  opt.on_tail('--version', 'Prints the version number and exits') do
+  
+  opt.on_tail('--version', "Prints the version number and exits") do
     puts FormatStaged::VERSION
     exit
   end
-
-  opt.on('--[no-]color', 'Colorizes output') do |value|
-    parameters[:color_output] = value
-  end
 end
 
 parser.parse!
 parameters[:patterns] = ARGV
 
-if !parameters[:formatter] || parameters[:patterns].empty?
-  puts 'Missing formatter or file patterns!'
-
+if !parameters[:formatter] or parameters[:patterns].empty?
+  puts "Missing formatter or file patterns!"
+  
   puts parser
   exit
 end
 
-begin
-  success = FormatStaged.run(**parameters)
-  exit success ? 0 : 1
-rescue RuntimeError => e
-  puts "💣 Error: #{e.message}".red
-  exit 1
-end
+formatter = FormatStaged.new(**parameters)
+formatter.run
diff --git a/examples/pre-commit.rubocop b/examples/pre-commit.rubocop
deleted file mode 100755
index c5ffa7a..0000000
--- a/examples/pre-commit.rubocop
+++ /dev/null
@@ -1,2 +0,0 @@
-#!/bin/sh
-bundle exec git-format-staged -f "bundle exec rubocop -x -s {} --stderr"  "*.rb" --verbose
\ No newline at end of file
diff --git a/format-staged.gemspec b/format-staged.gemspec
index ddde6c8..df36505 100644
--- a/format-staged.gemspec
+++ b/format-staged.gemspec
@@ -1,25 +1,16 @@
-# frozen_string_literal: true
-
-lib = File.expand_path('lib', __dir__)
+lib = File.expand_path("lib", __dir__)
 $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
 require 'format-staged/version'
 
 Gem::Specification.new do |s|
   s.name        = 'format-staged'
   s.version     = FormatStaged::VERSION
-  s.summary     = 'git format staged!'
-  s.description = 'git format staged'
-  s.authors     = ['Sven Weidauer']
+  s.summary     = "git format staged!"
+  s.description = "git format staged"
+  s.authors     = ["Sven Weidauer"]
   s.email       = 'sven@5sw.de'
   s.files       = Dir['lib/**/*.rb']
   s.executables << 'git-format-staged'
   s.homepage    = 'https://github.com/5sw/format-staged'
   s.license     = 'MIT'
-  s.required_ruby_version = '>= 2.7'
-
-  s.add_dependency 'colorize'
-
-  s.metadata = {
-    'rubygems_mfa_required' => 'true'
-  }
 end
diff --git a/lib/format-staged.rb b/lib/format-staged.rb
new file mode 100644
index 0000000..69e7c48
--- /dev/null
+++ b/lib/format-staged.rb
@@ -0,0 +1,109 @@
+require 'format-staged/version'
+require 'format-staged/entry'
+require 'format-staged/io'
+require 'shellwords'
+
+class FormatStaged 
+  attr_reader :formatter, :patterns, :update, :write, :verbose
+  
+  def initialize(formatter:, patterns:, update: true, write: true, verbose: true) 
+    @formatter = formatter
+    @patterns = patterns
+    @update = update
+    @write = write
+    @verbose = verbose
+  end
+  
+  def run()
+    root = get_output('git', 'rev-parse', '--show-toplevel').first
+    
+    files = get_output('git', 'diff-index', '--cached', '--diff-filter=AM', '--no-renames', 'HEAD')
+      .map { |line| Entry.new(line, root: root) }
+      .reject { |entry| entry.symlink? }
+      .filter { |entry| entry.matches?(@patterns) }
+      
+      files.each do |file|
+        format_file(file)
+      end
+    end
+    
+    def format_file(file) 
+      new_hash = format_object file
+      
+      return true if not write 
+
+      if new_hash == file.dst_hash
+        puts "Unchanged #{file.src_path}"
+        return false
+      end
+      
+      if object_is_empty new_hash
+        puts "Skipping #{file.src_path}, formatted file is empty"
+        return false
+      end
+
+      replace_file_in_index file, new_hash
+      
+      if update
+        begin
+          patch_working_file file, new_hash
+        rescue => error
+          puts "Warning: failed updating #{file.src_path} in working copy: #{error}"
+        end
+      end
+      
+      true
+    end
+    
+    def format_object(file)
+      puts "Formatting #{file.src_path}"
+      
+      format_command = formatter.sub("{}", file.src_path.shellescape)
+      
+      pid1, r = pipe_command "git", "cat-file", "-p", file.dst_hash
+      pid2, r = pipe_command format_command, source: r
+      pid3, r = pipe_command "git", "hash-object", "-w", "--stdin", source: r
+      
+      result = r.readlines.map { |it| it.chomp }
+      if @verbose
+        result.each do |line|
+          puts "< #{line}"
+        end
+      end
+    
+      Process.wait pid1
+      raise "Cannot read #{file.dst_hash} from object database" unless $?.success?
+      
+      Process.wait pid2
+      raise "Error formatting #{file.src_path}" unless $?.success?
+      
+      Process.wait pid3
+      raise "Error writing formatted file back to object database" unless $?.success? && !result.empty?
+      
+      result.first
+    end
+    
+    def object_is_empty(hash)
+      size = get_output("git", "cat-file", "-s", hash).first.to_i
+      size == 0
+    end
+
+    def patch_working_file(file, new_hash)
+      patch = get_output "git", "diff", file.dst_hash, new_hash, lines: false
+      patch.gsub! "a/#{file.dst_hash}", "a/#{file.src_path}"
+      patch.gsub! "b/#{new_hash}", "b/#{file.src_path}"
+
+      input, patch_out = IO.pipe
+      pid, r = pipe_command "git", "apply", "-", source: input
+      
+      patch_out.write patch
+      patch_out.close
+      
+      Process.wait pid
+      raise "Error applying patch" unless $?.success?
+    end
+
+    def replace_file_in_index(file, new_hash)
+      get_output "git", "update-index", "--cacheinfo", "#{file.dst_mode},#{new_hash},#{file.src_path}"
+    end
+end
diff --git a/lib/format-staged/entry.rb b/lib/format-staged/entry.rb
index 3828903..5f58847 100644
--- a/lib/format-staged/entry.rb
+++ b/lib/format-staged/entry.rb
@@ -1,23 +1,9 @@
-# frozen_string_literal: true
-
-module FormatStaged
-  ##
-  # Entry in the git index.
-  #
-  # Data as produced by `git diff-index`
+class FormatStaged 
   class Entry
-    PATTERN = /^
-      :(?<src_mode>\d+)\s
-      (?<dst_mode>\d+)\s
-      (?<src_hash>[a-f0-9]+)\s
-      (?<dst_hash>[a-f0-9]+)\s
-      (?<status>[A-Z])(?<score>\d+)?\t
-      (?<src_path>[^\t]+)
-      (?:\t(?<dst_path>[^\t]+))?
-      $/x.freeze
+    PATTERN = /^:(?<src_mode>\d+) (?<dst_mode>\d+) (?<src_hash>[a-f0-9]+) (?<dst_hash>[a-f0-9]+) (?<status>[A-Z])(?<score>\d+)?\t(?<src_path>[^\t]+)(?:\t(?<dst_path>[^\t]+))?$/
 
     attr_reader :src_mode, :dst_mode, :src_hash, :dst_hash, :status, :score, :src_path, :dst_path, :path, :root
-
+    
     def initialize(line, root:)
       matches = line.match(PATTERN) or raise "Cannot parse output #{line}"
       @src_mode = matches[:src_mode]
@@ -31,15 +17,17 @@ module FormatStaged
       @path = File.expand_path(@src_path, root)
       @root = root
     end
-
+    
     def symlink?
       @dst_mode == '120000'
     end
-
+    
     def matches?(patterns)
       result = false
       patterns.each do |pattern|
-        result = true if File.fnmatch? pattern, path, File::FNM_EXTGLOB
+        if File.fnmatch? pattern, path, File::FNM_EXTGLOB
+          result = true
+        end
       end
       result
     end
diff --git a/lib/format-staged/io.rb b/lib/format-staged/io.rb
index 8d3bf5d..44a447b 100644
--- a/lib/format-staged/io.rb
+++ b/lib/format-staged/io.rb
@@ -1,77 +1,40 @@
-# frozen_string_literal: true
-
-require 'English'
-
-module FormatStaged
-  ##
-  # Mixin that provides IO methods
-  module IOMixin
-    def get_output(*args, lines: true, silent: false)
-      puts "> #{args.join(' ')}" if @verbose
-
-      r = IO.popen(args, err: :err)
-      output = read_output(r, lines: lines, silent: silent)
-
-      raise 'Failed to run command' unless $CHILD_STATUS.success?
-
-      output
-    end
-
-    def get_status(*args)
-      puts "> #{args.join(' ')}" if @verbose
-      result = system(*args)
-
-      raise 'Failed to run command' if result.nil?
-
-      puts "? #{$CHILD_STATUS.exitstatus}" if @verbose
-
-      $CHILD_STATUS.exitstatus
-    end
-
-    def pipe_command(*args, source: nil)
-      puts (source.nil? ? '> ' : '| ') + args.join(' ') if @verbose
-      r, w = IO.pipe
-
-      opts = {}
-      opts[:in] = source unless source.nil?
-      opts[:out] = w
-      opts[:err] = :err
-
-      pid = spawn(*args, **opts)
-
-      w.close
-      source&.close
-
-      [pid, r]
-    end
-
-    def read_output(output, lines: true, silent: false)
-      result = output.read
-      splits = result.split("\n")
-      if @verbose && !silent
-        splits.each do |line|
-          puts "< #{line}"
-        end
+class FormatStaged 
+  def get_output(*args, lines: true)
+    puts '> ' + args.join(' ') if @verbose
+    
+    output = IO.popen(args, err: :err) do |io|
+      if lines
+        io.readlines.map { |l| l.chomp }
+      else
+        io.read
       end
-      output.close
-
-      lines ? splits : result
     end
-
-    def fail!(message)
-      abort "💣  #{message.red}"
-    end
-
-    def warning(message)
-      warn "⚠️  #{message.yellow}"
-    end
-
-    def info(message)
-      puts message.blue
-    end
-
-    def verbose_info(message)
-      puts "ℹ️  #{message}" if verbose
+    
+    if @verbose and lines
+      output.each do |line|
+        puts "< #{line}"
+      end
     end
+    
+    raise "Failed to run command" unless $?.success?
+    
+    output
   end
+  
+  def pipe_command(*args, source: nil)
+    puts (source.nil? ? '> ' : '| ') + args.join(' ')  if @verbose
+    r, w = IO.pipe
+    
+    opts = {}
+    opts[:in] = source unless source.nil?
+    opts[:out] = w
+    opts[:err] = :err
+    
+    pid = spawn(*args, **opts)
+    
+    w.close
+    source &.close
+    
+    return [pid, r]
+  end  
 end
diff --git a/lib/format-staged/job.rb b/lib/format-staged/job.rb
deleted file mode 100644
index 176b099..0000000
--- a/lib/format-staged/job.rb
+++ /dev/null
@@ -1,157 +0,0 @@
-# frozen_string_literal: true
-
-require_relative 'entry'
-require_relative 'io'
-
-require 'shellwords'
-require 'colorize'
-require 'English'
-
-module FormatStaged
-  ##
-  # Runs staged changes through a formatting tool
-  class Job
-    include IOMixin
-
-    attr_reader :formatter, :patterns, :update, :write, :verbose
-
-    def initialize(formatter:, patterns:, **options)
-      validate_patterns patterns
-
-      @formatter = formatter
-      @patterns = patterns
-      @update = options.fetch(:update, true)
-      @write = options.fetch(:write, true)
-      @verbose = options.fetch(:verbose, true)
-
-      String.disable_colorization = !options.fetch(:color_output, $stdout.isatty)
-    end
-
-    def run
-      files = matching_files(repo_root)
-      if files.empty?
-        info 'No staged file matching pattern. Done'
-        return true
-      end
-
-      formatted = files.filter { |file| format_file file }
-
-      return false unless formatted.size == files.size
-
-      quiet = @verbose ? [] : ['--quiet']
-      !write || get_status('git', 'diff-index', '--cached', '--exit-code', *quiet, 'HEAD') != 0
-    end
-
-    def repo_root
-      verbose_info 'Finding repository root'
-      root = get_output('git', 'rev-parse', '--show-toplevel', lines: false).chomp
-      verbose_info "Repo at #{root}"
-
-      root
-    end
-
-    def matching_files(root)
-      verbose_info 'Listing staged files'
-
-      get_output('git', 'diff-index', '--cached', '--diff-filter=AM', '--no-renames', 'HEAD')
-        .map { |line| Entry.new(line, root: root) }
-        .reject(&:symlink?)
-        .filter { |entry| entry.matches?(@patterns) }
-    end
-
-    def format_file(file)
-      new_hash = format_object file
-
-      return true unless write
-
-      if new_hash == file.dst_hash
-        info "Unchanged #{file.src_path}"
-        return true
-      end
-
-      if object_is_empty new_hash
-        info "Skipping #{file.src_path}, formatted file is empty"
-        return false
-      end
-
-      replace_file_in_index file, new_hash
-      update_working_copy file, new_hash
-
-      if new_hash == file.src_hash
-        info "File #{file.src_path} equal to comitted"
-        return true
-      end
-
-      true
-    end
-
-    def update_working_copy(file, new_hash)
-      return unless update
-
-      begin
-        patch_working_file file, new_hash
-      rescue StandardError => e
-        warning "failed updating #{file.src_path} in working copy: #{e}"
-      end
-    end
-
-    def format_object(file)
-      info "Formatting #{file.src_path}"
-
-      format_command = formatter.sub('{}', file.src_path.shellescape)
-
-      pid1, r = pipe_command 'git', 'cat-file', '-p', file.dst_hash
-      pid2, r = pipe_command format_command, source: r
-
-      write_args = write ? ['-w'] : []
-      pid3, r = pipe_command 'git', 'hash-object', *write_args, '--stdin', source: r
-
-      result = read_output(r, lines: false).chomp
-
-      Process.wait pid1
-      raise "Cannot read #{file.dst_hash} from object database" unless $CHILD_STATUS.success?
-
-      Process.wait pid2
-      raise "Error formatting #{file.src_path}" unless $CHILD_STATUS.success?
-
-      Process.wait pid3
-      raise 'Error writing formatted file back to object database' unless $CHILD_STATUS.success? && !result.empty?
-
-      result
-    end
-
-    def object_is_empty(hash)
-      size = get_output('git', 'cat-file', '-s', hash).first.to_i
-      size.zero?
-    end
-
-    def patch_working_file(file, new_hash)
-      info 'Updating working copy'
-
-      patch = get_output 'git', 'diff', file.dst_hash, new_hash, lines: false, silent: true
-      patch.gsub! "a/#{file.dst_hash}", "a/#{file.src_path}"
-      patch.gsub! "b/#{new_hash}", "b/#{file.src_path}"
-
-      input, patch_out = IO.pipe
-      pid, r = pipe_command 'git', 'apply', '-', source: input
-
-      patch_out.write patch
-      patch_out.close
-
-      read_output r
-
-      Process.wait pid
-      raise 'Error applying patch' unless $CHILD_STATUS.success?
-    end
-
-    def replace_file_in_index(file, new_hash)
-      get_output 'git', 'update-index', '--cacheinfo', "#{file.dst_mode},#{new_hash},#{file.src_path}"
-    end
-
-    def validate_patterns(patterns)
-      patterns.each do |pattern|
-        fail! "Negative pattern '#{pattern}' is not yet supported" if pattern.start_with? '!'
-      end
-    end
-  end
-end
diff --git a/lib/format-staged/version.rb b/lib/format-staged/version.rb
index d9e035e..dc206b1 100644
--- a/lib/format-staged/version.rb
+++ b/lib/format-staged/version.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
-module FormatStaged
-  VERSION = '0.1.2'
-end
+class FormatStaged
+  VERSION = "0.0.1"
+end
\ No newline at end of file
diff --git a/lib/format_staged.rb b/lib/format_staged.rb
deleted file mode 100644
index 683244f..0000000
--- a/lib/format_staged.rb
+++ /dev/null
@@ -1,12 +0,0 @@
-# frozen_string_literal: true
-
-require_relative 'format-staged/job'
-require_relative 'format-staged/version'
-
-##
-# FormatStaged module
-module FormatStaged
-  def self.run(**options)
-    Job.new(**options).run
-  end
-end
diff --git a/spec/git.rb b/spec/git.rb
deleted file mode 100644
index 7ffa1e3..0000000
--- a/spec/git.rb
+++ /dev/null
@@ -1,88 +0,0 @@
-# frozen_string_literal: true
-
-require 'tmpdir'
-require 'fileutils'
-require 'English'
-
-##
-# Test helpers for managing a git repository
-module Git
-  ##
-  # A git repository
-  class Repo
-    attr_reader :path
-
-    def initialize
-      @path = Dir.mktmpdir
-
-      git 'init', '-b', 'main'
-      git 'config', 'user.name', 'Test User'
-      git 'config', 'user.email', 'test@example.com'
-    end
-
-    def file_in_tree(name, content)
-      set_content name, content
-      stage name
-      commit "Add #{name}"
-    end
-
-    def set_content(name, content)
-      absolute = Pathname.new(path) + name
-
-      FileUtils.mkdir_p absolute.dirname
-      File.write absolute, content.end_with?("\n") ? content : "#{content}\n"
-    end
-
-    def get_content(name)
-      File.read(Pathname.new(path) + name).chomp
-    end
-
-    def get_staged(name)
-      git 'show', ":#{name}"
-    end
-
-    def stage(file)
-      git 'add', file
-    end
-
-    def commit(message)
-      git 'commit', '-m', message
-    end
-
-    def content(file)
-      git 'show', ":#{file}"
-    end
-
-    def cleanup
-      FileUtils.remove_entry path
-    end
-
-    def git(*cmd)
-      in_repo do
-        output = IO.popen(['git'] + cmd) do |io|
-          io.read.chomp
-        end
-
-        raise 'Failed to run git' unless $CHILD_STATUS.success?
-
-        output
-      end
-    end
-
-    def in_repo(&block)
-      Dir.chdir path, &block
-    end
-
-    def run_formatter(**arguments)
-      in_repo do
-        FormatStaged.run(**arguments, formatter: "#{__dir__}/test_hook.rb {}", patterns: ['*.test'])
-      end
-    end
-  end
-
-  def self.new_repo
-    repo = Repo.new
-    yield repo if block_given?
-    repo
-  end
-end
diff --git a/spec/test_hook.rb b/spec/test_hook.rb
deleted file mode 100755
index 595050e..0000000
--- a/spec/test_hook.rb
+++ /dev/null
@@ -1,13 +0,0 @@
-#!/usr/bin/env ruby
-# frozen_string_literal: true
-
-output = []
-$stdin.readlines.each do |line|
-  exit 0 if line.chomp == '#clear'
-  exit 1 if line.chomp == '#fail'
-  output << line.gsub(/([^\s]*)\s*=\s*(.*)/, '\1 = \2')
-end
-
-output.each do |line|
-  puts line
-end
diff --git a/spec/test_hook_spec.rb b/spec/test_hook_spec.rb
deleted file mode 100644
index 236279d..0000000
--- a/spec/test_hook_spec.rb
+++ /dev/null
@@ -1,34 +0,0 @@
-# frozen_string_literal: true
-
-require 'English'
-
-describe 'Test Hook' do
-  it 'adds spaces around =' do
-    out = run 'a=b'
-
-    expect(out).to eq('a = b')
-  end
-
-  it 'returns empty output if it as a #clear line' do
-    out = run "a=b\n#clear\nc = d"
-    expect(out).to eq ''
-  end
-
-  it 'fails with a #fail line' do
-    expect { run '#fail' }.to raise_error(RuntimeError) { |error|
-      expect(error.message).to eq('Cannot run test_hook.rb')
-    }
-  end
-
-  def run(input)
-    result = IO.popen ['ruby', "#{__dir__}/test_hook.rb"], mode: File::RDWR do |io|
-      io.write input
-      io.close_write
-      io.read.chomp
-    end
-
-    raise 'Cannot run test_hook.rb' unless $CHILD_STATUS.success?
-
-    result
-  end
-end
diff --git a/spec/test_spec.rb b/spec/test_spec.rb
deleted file mode 100644
index 26fc0ff..0000000
--- a/spec/test_spec.rb
+++ /dev/null
@@ -1,139 +0,0 @@
-# frozen_string_literal: true
-
-require_relative 'git'
-
-require 'format_staged'
-
-describe FormatStaged do
-  def repo
-    @repo ||= Git.new_repo do |repo|
-      repo.file_in_tree 'origin.test', 'x = y'
-    end
-  end
-
-  after :each do
-    @repo&.cleanup
-    @repo = nil
-  end
-
-  it 'updates staged file and working copy' do
-    repo.set_content 'test.test', 'a=b'
-    repo.stage 'test.test'
-    success = repo.run_formatter
-
-    expect(success).to be_truthy
-    expect(repo.get_staged('test.test')).to eq('a = b')
-    expect(repo.get_content('test.test')).to eq('a = b')
-  end
-
-  it 'leaves other changes in working copy' do
-    repo.set_content 'test.test', "x=y\na=b\n"
-    repo.stage 'test.test'
-    repo.set_content 'test.test', 'abc'
-    success = repo.run_formatter
-
-    expect(success).to be_truthy
-    expect(repo.get_content('test.test')).to eq('abc')
-    expect(repo.get_staged('test.test')).to eq("x = y\na = b")
-  end
-
-  it 'merges update to working copy' do
-    repo.set_content 'test.test', "x=y\n#stuff\n"
-    repo.stage 'test.test'
-    repo.set_content 'test.test', "x=y\n#stuff\nmore stuff\n"
-    success = repo.run_formatter
-
-    expect(success).to be_truthy
-    expect(repo.get_content('test.test')).to eq("x = y\n#stuff\nmore stuff")
-    expect(repo.get_staged('test.test')).to eq("x = y\n#stuff")
-  end
-
-  it 'only touches files matching the given pattern' do
-    repo.set_content 'test.other', 'x=y'
-    repo.stage 'test.other'
-    success = repo.run_formatter
-
-    expect(success).to be_truthy
-    expect(repo.get_content('test.other')).to eq('x=y')
-  end
-
-  it 'fails if all files are changed to already comitted version' do
-    repo.file_in_tree 'test.test', 'x = y'
-    repo.set_content 'test.test', 'x=y'
-    repo.stage 'test.test'
-
-    success = repo.run_formatter
-
-    expect(success).to be_falsy
-    expect(repo.get_content('test.test')).to eq('x = y')
-  end
-
-  it 'succeeds if there are excluded files to commit' do
-    repo.file_in_tree 'test.test', 'x = y'
-    repo.set_content 'test.test', 'x=y'
-    repo.stage 'test.test'
-    repo.set_content 'test.other', 'abc'
-    repo.stage 'test.other'
-
-    success = repo.run_formatter
-
-    expect(success).to be_truthy
-    expect(repo.get_content('test.test')).to eq('x = y')
-  end
-
-  it 'succeeds if there are no staged files' do
-    expect(repo.run_formatter).to be_truthy
-  end
-
-  it 'succeeds if only excluded files are changed' do
-    repo.set_content 'test.other', 'abc'
-    repo.stage 'test.other'
-
-    expect(repo.run_formatter).to be_truthy
-  end
-
-  it 'succeeds if one file is changed' do
-    repo.file_in_tree 'test.test', 'x = y'
-    repo.set_content 'test.test', 'x=y'
-    repo.stage 'test.test'
-    repo.set_content 'other.test', 'a=b'
-    repo.stage 'other.test'
-
-    success = repo.run_formatter
-
-    expect(success).to be_truthy
-    expect(repo.get_content('test.test')).to eq('x = y')
-    expect(repo.get_content('other.test')).to eq('a = b')
-  end
-
-  it 'fails if a single file becomes empty' do
-    repo.file_in_tree 'test.test', 'x = y'
-    repo.set_content 'test.test', '#clear'
-    repo.stage 'test.test'
-    repo.set_content 'other.test', 'a=b'
-    repo.stage 'other.test'
-
-    success = repo.run_formatter
-
-    expect(success).to be_falsy
-    expect(repo.get_content('test.test')).to eq('#clear')
-    expect(repo.get_content('other.test')).to eq('a = b')
-  end
-
-  it 'fails if the hook returns a nonzero status' do
-    repo.set_content 'test.test', '#fail'
-    repo.stage 'test.test'
-    expect { repo.run_formatter }.to raise_error(RuntimeError) { |error|
-      expect(error.message).to eq 'Error formatting test.test'
-    }
-  end
-
-  it 'leaves files alone when write is false' do
-    repo.set_content 'test.test', 'a=b'
-    repo.stage 'test.test'
-
-    expect(repo.run_formatter(write: false)).to be_truthy
-    expect(repo.get_content('test.test')).to eq 'a=b'
-    expect(repo.get_staged('test.test')).to eq 'a=b'
-  end
-end