radareorg/radare2

Radare2 is a free, open-source reverse engineering framework and collection of command-line tools. Reverse engineering, in this context, means taking a compiled program, which is in binary machine code that humans cannot directly read, and analyzing it to understand what it does. This is used in security research, malware analysis, vulnerability discovery, and software forensics. Radare2 provides a disassembler (which converts machine code back into human-readable assembly language), a debugger (for stepping through a running program), a hex editor (for viewing and modifying raw binary data), and many analysis tools. You can open any executable file, or even raw memory from a running process, and inspect its structure, find functions, trace execution, search for patterns, and modify bytes in place. It supports an enormous range of CPU architectures (x86, ARM, MIPS, RISC-V, and dozens more) and runs on nearly every operating system including Linux, macOS, Windows, Android, and several BSDs. A plugin system extends its capabilities with decompilers, AI-assisted analysis, and integration with other tools. Scripting is supported from multiple programming languages via the r2pipe interface. You would use Radare2 when you need to analyze software at the binary level without source code access, for security auditing, CTF competitions, malware investigation, or understanding how a piece of software actually works internally. It is primarily a command-line tool written in C, with an optional graphical interface called iaito.