Dbx debugger

Dbx is a popular, Unix-based source-level debugger found primarily on Solaris and Berkeley systems. It provides symbolic debugging for programs written in C, C++, Pascal and FORTRAN.

Useful features include stepping through programs one source line at a time, or one machine instruction at a time. In addition to simply viewing operation of the program, variables can be assigned and a wide range of expressions can be evaluated and displayed.