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++, Fortran, Pascal 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.
dbx was originally developed at University of California, Berkeley, by Mark Linton during the years 1981–1984[1] and subsequently made its way to various vendors who had licensed BSD.