gdb gnu debugger gdb gdb emacs a.out emacs M-x gdb Run gdb (like this): gdb a.out gdb window main break main (gdb) (gdb) break main run main (gdb) run main disassemble disassemble disassemble main disassemble (gdb) disassemble main main disassemble stepi (gdb) stepi stepi step (gdb) info registers (gdb) print $ continue (gdb) continue main main (gdb) break * x (gdb) x x x/ 10 o b(byte), h(half), w