GDB old - Opty-Forks/SSof GitHub Wiki

GDB Basics

Below is a simple list of basic GDB commands. They should get you going for most of our exercises

• gdb ./file --- open GDB to debug file
• disas function --- disassemble function function
• disas address --- disassemble function at this address
• b address --- inserts a breakpoint at address address
• r < file --- run the program with input file
• s --- execute next step of program
• c --- execute until the next breakpoint of the program
• p expr --- prints the value expr. expr can be a var, the pointer to a var (its address), a register, etc. It can even be address1 - address2 and in this case returns the difference between the addresses.
• info f --- returns the info of a frame. Particularly usefull whenever you need to know where the return address of the function is stored and/or the value contained there.
• stack n --- show the n registers after the stack pointer
• x/nx $rsp --- show the n registers after the register $rsp
• x/nx address --- show the n registers after the address address