The nm command ships with a number of later versions of Unix and similar operating systems. nm is used to examine binary files (including libraries, compiled object modules, shared-object files, and standalone executables) and to display the contents of those files, or meta information stored in them. nm is used as an aid for debugging, to help resolve problems arising from name conflicts and C++ name mangling, and to validate other parts of the toolchain.

The GNU project ships a highly capable nm program as part of the GNU Binutils package. As with other parts of the GNU toolchain, a given nm binary is compiled only for a specific computer architecture and binary format, and so security specialists who use nm to examine suspect binary files typically keep a number of "foreign target" nm binaries prebuilt.