This talk will discuss approaches for debugging codes. We will start with freely available open source debuggers such as gdb and those supplied with the compilers, such as PGI's pgdbg. Then we will spend the rest of the talk showing features of the commercial Totalview debugger which CHPC licenses. We start with basic serial debugging, followed by parallel OpenMP and MPI debugging, showing features and tips that improve the debugging experience. We will close up with additional Totalview features such as the Memory Debugging, Replay Engine and CUDA and Xeon Phi debugging features.