GDB question - how do I go through disassembled code line by line?

Question

I'd like to go through a binary file my teacher gave me line by line to check addresses on the stack and the contents of different registers, but I'm not extremely familiar with using gdb. Although I have the C code, we're supposed to work entirely from a binary file. Here are the commands I've used so far:

(gdb) file SomeCode

Which gives me this message:

Reading symbols from ../overflow/SomeCode ...(no debugging symbols found)...done.

Then I use :

(gdb) disas main

which gives me all of the assembly. I wanted to set up a break point and use the "next" command, but none of the commands I tried work. Does anyone know the syntax I would use?

Answer 1

try using ni which is nexti. equivalent is si which is step instruction

Answer 2

nexti if you want to jump over function calls. stepi if you want to enter a function call.

The following documentation is very helpful; it has a list of all the important commands you could use on gdb.

X86-64: http://csapp.cs.cmu.edu/public/docs/gdbnotes-x86-64.pdf

IA32: http://csapp.cs.cmu.edu/public/docs/gdbnotes-ia32.pdf