UPX
UPX, short for Ultimate Packer for eXecutables, is a free, open-source executable packer designed to reduce the size of binaries for distribution and storage. It supports a broad range of executable formats, including Windows Portable Executables (PE), Linux/Unix ELF binaries, and macOS Mach-O files, as well as many object files and libraries. Packed files contain a small loader that decompresses the original code and data at runtime, allowing the program to run normally after startup.
UPX uses multiple compression backends, notably LZMA-based methods and PPMd, enabling users to choose between higher
While UPX can substantially reduce file size, the decompression step can introduce a small startup delay, and
UPX is distributed under the UPX License, a permissive free software license. It is widely used by