Some Useful Commands in GDB

I would like to list common useful commands in gdb:

(gdb) b main
set up a break point at main function after function prologue

(gdb) b *main
set up a break point right at the address of main, so that when $pc points to *main, it will break

(gdb) delete 1
delete break point 1

(gdb) p/d i
print the content of variable i as a signed decimal

(gdb) p/u j
print the content of variable j as an unsigned decimal

(gdb) p/x k
print the content of variable k in hex

(gdb) x/5i $pc
print next 5 instructions in assembly

(gdb) x/s buffer
print string at address pointed by variable buffer

(gdb) x/xg 0x123456789abcdef0
print 64-bit value in hex at address 0x123456789abcdef0

(gdb) x/10wx {void*}$rbp
print 10 consecutive 32-bit values in hex starting from the address pointed by $rbp register

(gdb) info reg
examine all the register values

(gdb) r arg1 arg2
run the program with command-line argument arg1 and arg2

(gdb) si
execute one machine instruction; if it is a function call, step into the subroutine

(gdb) ni
execute one machine instruction; if it is a function call, do not step into the subroutine

(gdb) step
execute one line of C/C++ code; step into function

(gdb) next
execute one line of C/C++ code; step over function

(gdb) p func(arg1, arg2)
print return value by calling function func with arguments arg1 and arg2

(gdb) finish
continue execution until the end of current frame (i.e., subroutine)

(gdb) disass main
show assembly instructions of main function

(gdb) list main.c:37
display source code of main.c file at around line 37

(gdb) display/i $pc
keep displaying next machine instruction

(gdb) until 37
continue execution until the specified line