The GNU Debugger, GDB, is the standard debugger on GNU/Linux and BSD systems and can be used on just about any Unix system with a C compiler and at least one of several well-known object file formats. It can also be used on other kinds of systems as well. GDB has a very rich feature set, making it the preferred debugger of many developers the world over.
This pocket reference provides a complete summary of GDB command-line syntax, initialization files, expressions, variables, and commands. It also describes the source code locations for GDB and two other graphical debuggers based on GDB.
A full introduction to GDB may be found in itsa documentation, which is included in the source code. This documentation is also available from the Free Software Foundation in Debugging with GDB: The GNU Source-Level Debugger, by Richard M. Stallman, Roland Pesch, Stan Shebs, et al.