Mach-O

Mach-O (Mach Object) is a file format used for executables, object code, shared libraries, and core dumps on macOS, iOS, and other Apple operating systems. It is the standard binary format for these platforms, replacing the earlier a.out format, and is designed to support features like dynamic linking, code signing, and multi-architecture binaries.

Also known as: Mach Object, Mach-O format, Mach Object File Format, Mach-O binary, Mach-O executable

Why learn Mach-O?

Developers should learn Mach-O when working on Apple platforms (macOS, iOS, tvOS, watchOS) to understand how applications are structured, debug binary issues, or perform reverse engineering. It is essential for tasks like analyzing crash dumps, optimizing performance, or developing tools that interact with executable files, such as debuggers or security scanners.

Learning Resources

• docs: Apple Developer Documentation: Mach-O File Format
• book: OS X Internals: A Systems Approach - Mach-O Chapter
• tutorial: Mach-O File Format Tutorial by Jonathan Levin
• video: Reverse Engineering macOS: Mach-O Binaries (YouTube Video)