UBThinner

A Script to thin Universal Apps on macOS quickly. It traverses through the given folder recursively, identifies any universal binaries and thins them using lipo. The default arch that is thinned is the opposite of your system's. Example - if you are on any M1 device, then your system arch is arm64, so x86_64 portions will be removed from every universal binary within the given folder/app.

Usage

Usage: UBThinner[.sh/.py] appDir [options]
Options:
 -b, makes a backup of the app
 -c, makes a copy of the app and modifies it instead of the original app
 -q, quiets the output
 -r, reverses the architecture to remove (for testing purposes or to send a thinned app to someone else)
 -p, only prints list of files that can be thinned (lipo is not called)

Notes

• You will probably need the XCode Command Line Tools for lipo, install them in terminal by running xcode-select --install
• The .cpp file can be compiled using g++, which also needs the command line tools. After installing them, run the following g++ -std=c++17 UBThinner.cpp -o UBThinner
• If you get the Directory not writeable. Copy it to another folder where it can be written to error than you can either copy the app elsewhere (to the Documents folder for example) and run UBThinner there or you can run it as root. (su -> enter password -> run UBThinner)
• I first made it in bash, which is why comments are included only in the .sh file. Then I ported the code to python. Lastly, I thought of trying it out in C++ to see how the speeds would compare. I used std::filesystem from C++17 to remain sane.
• The bash script is quite obviously the slowest. There is not much difference between the python and cpp scripts on my machine (M1 Air 8/256 GB)