What are the essential GDB commands for examining a binary?

disas shows code, x/ examines memory, info registers shows CPU state, and break + run drive execution.

Disassembly:

(gdb) disas phase_1
(gdb) disas 0x400da0,0x400dc0

Examine memory — x/NFT address:

(gdb) x/s  0x402490
(gdb) x/d  0x402490
(gdb) x/x  0x402490
(gdb) x/8a 0x402500
(gdb) x/6d $rsp
(gdb) x/10i main

Format: N = count, F = format (string, decimal, hex, address, instruction, char), T = size (byte, word=4, giant=8)

Registers:

(gdb) info registers
(gdb) p $eax
(gdb) p/x $rdi
(gdb) p/c $al

Go deeper:

• GDB manual: Examining Memory — the x/nfu command (formats, sizes, addresses)
• GDB manual: Source and Machine Code — the disassemble command
• Wikipedia: GNU Debugger — overview of print, examine, and register inspection