Batch rename files replacing periods with hyphens excluding the period in the file extension

Here is a quick and dirty Python script that does what you want.

See instructions on how to use below. The code is pretty straightfor

import os
from glob import glob

os.chdir("/Users/user/test")  #change this to the path to the directory with files to rename
for file in glob("*.ai"): #change ai to another extension, or use * to apply to all extensions
    separator = file.rfind(".")
    name, extension = file[:separator], file[separator:]
    name = name.replace(".","-")
    os.rename(file,name+extension)

To use, first replace "/Users/user/test" with the correct path for your files.

The above example applies to files with extension .ai in the selected folder, but you can change it to another extension, say, .pdf, or use "*.*" for files with any extension.

Save the contents to a file, like "replacedots.py".

To run the code,

1) open a Terminal window and type

"python "

WITH a SPACE at the end; DO NOT press enter

2) Drag the replacedots.py file over the Terminal window

3) Press enter

Done.

You can even do this briskly in the Terminal, once you have changed directory to the folder containing these multi-dot filenames and using the Zsh shell:

cd ~/Desktop/Test
autoload -U zmv
zmv '(*).(*)' '${1//./-}.$2'

That renames any multi-dot filename, regardless of the extension, to a filename replacing the dots with a dash and the original extension.

And here is the Ruby version that works with the System Ruby 2.6.10p210 (this example) or the latest Ruby 3.4.8:

#!/usr/bin/ruby
# frozen_string_literal: false

# Usage: ./notdot.rb ~/Desktop/Test

require 'pathname'
require 'fileutils'

f = File.expand_path(ARGF.filename)

Pathname.glob(File.join(f, '*.{ai,psd}')).each do |z|
  next unless FileTest.size?(z.to_path)

  zpath = z.to_path
  outfile = zpath.split('.')[0..-2].join('-') + z.extname
  FileUtils.mv(zpath, outfile, verbose: true)
end
exit

One simply changes the she-bang to #!/usr/bin/env ruby if using a privately installed Ruby 3.4.8 (as I do). One runs it as follows:

chmod +x ./nodot.rb
./nodot.rb ~/Desktop/Test

and the output will look like this for those non-empty target files:

mv /Users/viking/Desktop/Test/Baz_2.3.5.1.ai /Users/viking/Desktop/Test/Baz_2-3-5-1.ai
mv /Users/viking/Desktop/Test/Foo_1.2.3.4.psd /Users/viking/Desktop/Test/Foo_1-2-3-4.psd

Tested: Ruby 2.6.10, 3.4.8 and macOS Tahoe 26.1

AglaVerin wrote:

VikingOSX wrote:

You can even do this briskly in the Terminal, once you have changed directory to the folder containing these multi-dot filenames and using the Zsh shell:

cd ~/Desktop/Test

autoload -U zmv

zmv '(*).(*)' '${1//./-}.$2'

That renames any multi-dot filename, regardless of the extension, to a filename replacing the dots with a dash and the original extension.

Thank you for all these lines of codes. I'm unfamiliar with Python, do all these various workarounds you've offered require downloading Python in some form or do some only require Terminal / ready built in apps? Thanks!

@VikingOSX's code snippet in your quote here is actually for Zsh.

All of @VikingOSX's code in this thread so far requires no outside resources.....it can all be run with a default macOS installation since it utilizes Zsh commands or Ruby commands...all available with a default macOS installation.

Now, @Luis Sequeira1's Python code does require downloading outside resources since macOS no longer ships with Python. If you want to use Python, then it is best to download Python directly from the source/developer since Apple's XCode Command Line Utilities tend to use outdated versions of Python and it can be tricky updating the XCode Command Line Utilities.

https://www.python.org/

Unless you are going to be using Python for other things, using either of @VikingOSX's two options (or three options I guess) would be the better choice only because you don't need to install any extra items. All things being equal, I always prefer to minimize the amount of third party software I install on my devices.

You can do that and a lot more with Name Mangler.

Here's a list of the various renaming it can do:

Errata:

Replace this line:

for f in ${STARTDIR}/**/*.${~PATTERN}(.N);

with:

for f in ${STARTDIR}/**/*.(${~PATTERN})(.NL+0);

So that all non-empty files whose extensions in the PATTERN are processed. Until this is changed, it will only just process ".ai" files and ignore ".psd" files.

Thanks, good point about this coming from XCode command line tools. I think I knew that at some point, but forgot about it.

I know that 3.9 is extremely old and that the current version, as of late 2025, is 3.14.

But for the purpose of a simple script like this it would not matter. I currently use 3.12, by the way.

All of my code that I provided is run in the Terminal. Two of my code solutions require the Zsh shell which is already installed by macOS. For simplicity, I would just use the Zsh shell which precludes any programmer's editor requirement to preserve indent structure of Python or Ruby, or the actual download/installation of Python 3 from Python.org.

That Python 3.9 binary is the result of installing the ~ 4 GB Command Line Tools for Xcode. It is woefully out of date, though may still run your generic Python code as python3.

Since Apple stopped including Python in the operating system after Monterey 12.3.1, you can avoid installing Python 3.14 from Python.org. You can use this Zsh script even if you continue to use the Bash shell. This script only takes one argument on the Terminal command line, the path to the folder to process.

#!/bin/zsh

:<<"COMMENT"
A script to recursively (if relevant) rename all files in a designated folder
hierarchy from the format Bob 5.4.2.1.ai to Bob 5-4-2-1.ai.

Usage: chmod +x ./nodot.zsh
       ./nodot.zsh /Users/USERNAME/Desktop/Test
       ./nodot.zsh ~/Desktop/Test

Tested: Zsh 5.9, macOS 26.1

COMMENT

STARTDIR="${1:a:s/\~\//}"
[[ $# = 1 ]] || {echo "You need to specify the directory name to process"; exit 1}

# file extension pattern to process
PATTERN="ai|psd"

# force case-insenstive filenames and extensions
setopt nocaseglob

for f in ${STARTDIR}/**/*.${~PATTERN}(.N);
do
    mv "${f}" "${${f:r}//\./-}.${f:e}"
done
echo "Done"
exit 0

VikingOSX wrote:

Since Apple stopped including Python in the operating system after Monterey 12.3.1, you can avoid installing Python 3.14 from Python.org. You can use this Zsh script even if you continue to use the Bash shell. This script only takes one argument on the Terminal command line, the path to the folder to process.

That is a great script, and using only the built-in shell.

I do agree that your solution is better and more comprehensive than my admittedly quick hack.

Just a FWIW: Apple does include an old version of python (3.9), at least I have it at /usr/bin/python3 on my mac running Tahoe. So one would write the command as python3 instead of python (or add an alias).

Hi,

Another solution would be to use the Shortcuts application. Here is a self-contained shortcut you can download that would do just that: Replace Filename Dots with Dashes.

To use it, select the files in Finder, right-click them and choose Quick Actions > Replace Filename Dots with Dashes.