Mac OS X Office thinner: All files are link by hard link, so you needn't to worry about apple code signature. All same files are backuped to Trash dir

office-thinner.rb

#!/usr/bin/env ruby
# -*- coding:utf-8 -*-

# TODO: Check same file with soft link
# TODO: Trim same file by apfs clone

require 'set'
require 'find'
require 'digest'
require 'fileutils'

TRASH = "#{ENV["HOME"]}/.Trash/Office/"

WORD_PATH = '/Applications/Microsoft Word.app'
EXCEL_PATH = '/Applications/Microsoft Excel.app'
ONENOTE_PATH = '/Applications/Microsoft OneNote.app'
OUTLOOK_PATH =   '/Applications/Microsoft Outlook.app'
POWERPOINT_PATH = '/Applications/Microsoft PowerPoint.app'

PATHS = [WORD_PATH, EXCEL_PATH, ONENOTE_PATH, OUTLOOK_PATH, POWERPOINT_PATH]
@target_path = nil
@trim_paths = []

def find_all_files_without_prefix(dir)
  set = Set.new
  Find.find(dir) do |filename|
    unless File.directory? filename or File.symlink? filename
      set << filename[dir.length, filename.length] if filename != dir
    end
  end
  return set
end

def find_same_files(dir1, dir2)
  set1 = find_all_files_without_prefix(dir1)
  set2 = find_all_files_without_prefix(dir2)
  set = set1 & set2
  same_files = set.select do |filename|
    File.lstat(dir1+filename).ino != File.lstat(dir2+filename).ino \
      and FileUtils.compare_file(dir1+filename, dir2+filename)
  end
  return same_files
end

def backup_file(filename)
  dest_filename = TRASH + filename
  FileUtils.mkdir_p File.dirname(dest_filename)
  puts "Move #{filename} to #{dest_filename}"
  FileUtils.mv filename, dest_filename
end

def trim_all_same_files(target_dir, dir)
  same_files = find_same_files(target_dir, dir)
  same_files.each do |filename|
    backup_file dir+filename
    FileUtils.ln(target_dir+filename, dir+filename)
  end
end


def main
  if Process.euid != 0
    puts "Need root privilege, Please run: sudo ruby #{__FILE__}"
    exit 1
  end

  PATHS.each do |pathname|
    if Dir.exist?(pathname)
      if @target_path
        @trim_paths << pathname
      else
        @target_path = pathname
      end
    end
  end

  unless @target_path
    puts "Don't exist path in #{PATHS}"
    exit 1
  end

  puts "Trim #{@trim_paths} with #{@target_path}"
  @trim_paths.each do |pathname|
    puts "#{@target_path}, #{pathname}"
    trim_all_same_files(@target_path, pathname)
  end

  puts "Office thinning completed!"
  puts "Backup files in #{TRASH}, you view or delete the files later by Finder Trash."
end

if __FILE__ == $0
  main
end

Just run sudo ruby office-thinner.rb. All backup files are in ~/.Trash/Office

All files are link by hard link, so you needn't to worry about apple code signature. The script checks same file by content and file's inode number(to prevent repeated link).

I run into an error when using this script:

/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/find.rb:43:in `block in find': No such file or directory (Errno::ENOENT)
	from /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/find.rb:43:in `collect!'
	from /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/find.rb:43:in `find'
	from office-thinner.rb:20:in `find_all_files_with_no_prefix'
	from office-thinner.rb:30:in `find_same_files'
	from office-thinner.rb:47:in `trims_all_same_files'
	from office-thinner.rb:61:in `block in <main>'
	from office-thinner.rb:59:in `each'
	from office-thinner.rb:59:in `<main>'

Any idea?

I run into an error when using this script:

/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/find.rb:43:in `block in find': No such file or directory (Errno::ENOENT)
	from /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/find.rb:43:in `collect!'
	from /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/find.rb:43:in `find'
	from office-thinner.rb:20:in `find_all_files_with_no_prefix'
	from office-thinner.rb:30:in `find_same_files'
	from office-thinner.rb:47:in `trims_all_same_files'
	from office-thinner.rb:61:in `block in <main>'
	from office-thinner.rb:59:in `each'
	from office-thinner.rb:59:in `<main>'

Any idea?

Sorry, I did not receive this feedback.
Maybe that you did'nt have some paths of ["/Applications/Microsoft Word.app", "/Applications/Microsoft Excel.app", "/Applications/Microsoft OneNote.app", "/Applications/Microsoft Outlook.app", "/Applications/Microsoft PowerPoint.app"].
I changed the script to fix the issue. You can try the newest script.

hi @JackDrogon
I ran the script and it executed as expected but I see in Finder the app sizes still show up as earlier.
Is it because of hard linking? If yes how do I verify trimming has been done and how much is the resultant size of apps?

hi @JackDrogon
I ran the script and it executed as expected but I see in Finder the app sizes still show up as earlier.
Is it because of hard linking? If yes how do I verify trimming has been done and how much is the resultant size of apps?

Yep, because of hard link. You can see by running command df -hT.