gitignore-cleaner

#!/usr/bin/env ruby
# frozen_string_literal: true

# Find non-existing entries in gitignore
#
# For reference: https://git-scm.com/docs/gitignore
#
# @author Manuel Tancoigne <m.tancoigne@experimentslabs.com>
# @license MIT
# @version 0.2.0
#
#
# Usage
#     gitignore-cleaner                    # Use current directory
#     gitignore-cleaner path/to/repo       # Use .gitignore in "repo"
#     gitignore-cleaner path/to/.gitignore # Use specific gitignore
#
#
# Changelog:
#   0.2.0 - Support "!" lines, comments
#   0.1.0 - Initial creation

FILE = '.gitignore'

def message_and_exit(message, code = 1)
  puts message
  exit code
end

def determine_file(path = nil)
  return File.join(Dir.pwd, FILE) unless path

  message_and_exit 'Invalid path provided' unless File.exist? path

  return File.expand_path path if File.file? path

  full_path = File.join(path, FILE)
  message_and_exit "No #{FILE} found in \"#{path}\"" unless File.exist? full_path

  full_path
end

path    = determine_file ARGV[0]
base    = File.expand_path File.dirname path
content = File.read(path)
              .split("\n")
              .map(&:strip)
              # Remove empty lines
              .reject(&:empty?)
              # Ignore comments
              .grep_v(/^\s*#/)
              .map do |entry|
                # Handle "!" lines
                glob = entry.sub(/^!/, '')
                # Handle "/" lines
                glob = glob.match?(%r{^\s*/}) ? ".#{glob}" : "**/#{glob}"
                
                # Keep original entry for summary
                [entry, glob]
                end
                

missing = []
Dir.chdir base do
  missing = content.select { |entry| Dir.glob(entry[1]).count.zero? }
                   .map { |entry| entry[0] }
end

line_prefix = ' - '
puts <<~TXT
  #{missing.count}/#{content.count} unused entries#{missing.count.zero? ? ', great!' : ':'}
  #{line_prefix}#{missing.join("\n#{line_prefix}")}
TXT

No support for !file now. Done