DBX is a source-level debugger found primarily on Solaris, AIX, IRIX, Tru64 UNIX, Linux and BSD operating systems. It provides symbolic debugging for programs written in C, C++, Pascal, FORTRAN and Java. Useful features include stepping through programs one source line or machine instruction at a time. In addition to simply viewing operation of the program, variables can be manipulated and a wide range of expressions can be evaluated and displayed.