$ gcc -g -o helloworld helloworld.c

$ gdb -q helloworld
Reading symbols from helloworld...done.
gdb-peda$ set env LD_BIND_NOW
Setting environment variable "LD_BIND_NOW" to null value.
gdb-peda$ b main
Breakpoint 1 at 0x63e: file helloworld.c, line 21.
gdb-peda$ r
Starting program: /home/ubuntu/Dropbox/Workspace/c/doodle/helloworld
[----------------------------------registers-----------------------------------]
RAX: 0x55555555463a (<main>:    push   rbp)
RBX: 0x0
RCX: 0x555555554660 (<__libc_csu_init>: push   r15)
RDX: 0x7fffffffe368 --> 0x7fffffffe616 ("HOME=/home/ubuntu")
RSI: 0x7fffffffe358 --> 0x7fffffffe5e3 ("/home/ubuntu/Dropbox/Workspace/c/doodle/helloworld")
RDI: 0x1
RBP: 0x7fffffffe270 --> 0x555555554660 (<__libc_csu_init>:      push   r15)
RSP: 0x7fffffffe270 --> 0x555555554660 (<__libc_csu_init>:      push   r15)
RIP: 0x55555555463e (<main+4>:  lea    rdi,[rip+0x9f]        # 0x5555555546e4)
R8 : 0x7ffff7dd0d80 --> 0x0
R9 : 0x7ffff7dd0d80 --> 0x0
R10: 0x0
R11: 0x1
R12: 0x555555554530 (<_start>:  xor    ebp,ebp)
R13: 0x7fffffffe350 --> 0x1
R14: 0x0
R15: 0x0
EFLAGS: 0x246 (carry PARITY adjust ZERO sign trap INTERRUPT direction overflow)
[-------------------------------------code-------------------------------------]
   0x555555554635 <frame_dummy+5>:      jmp    0x5555555545a0 <register_tm_clones>
   0x55555555463a <main>:       push   rbp
   0x55555555463b <main+1>:     mov    rbp,rsp
=> 0x55555555463e <main+4>:     lea    rdi,[rip+0x9f]        # 0x5555555546e4
   0x555555554645 <main+11>:    call   0x555555554510 <puts@plt>
   0x55555555464a <main+16>:    mov    eax,0x0
   0x55555555464f <main+21>:    pop    rbp
   0x555555554650 <main+22>:    ret
[------------------------------------stack-------------------------------------]
0000| 0x7fffffffe270 --> 0x555555554660 (<__libc_csu_init>:     push   r15)
0008| 0x7fffffffe278 --> 0x7ffff7a05b97 (<__libc_start_main+231>:       mov    edi,eax)
0016| 0x7fffffffe280 --> 0x1
0024| 0x7fffffffe288 --> 0x7fffffffe358 --> 0x7fffffffe5e3 ("/home/ubuntu/Dropbox/Workspace/c/doodle/helloworld")
0032| 0x7fffffffe290 --> 0x100008000
0040| 0x7fffffffe298 --> 0x55555555463a (<main>:        push   rbp)
0048| 0x7fffffffe2a0 --> 0x0
0056| 0x7fffffffe2a8 --> 0xb753b8891c71e1e2
[------------------------------------------------------------------------------]
Legend: code, data, rodata, value

Breakpoint 1, main () at helloworld.c:21
21          printf("Hello world!\n");
gdb-peda$ x/i 0x555555554510
   0x555555554510 <puts@plt>:   jmp    QWORD PTR [rip+0x200aba]        # 0x555555754fd0
gdb-peda$ x/gx 0x555555754fd0
0x555555754fd0: 0x00007ffff7a649c0
gdb-peda$ x/4i 0x00007ffff7a649c0
   0x7ffff7a649c0 <_IO_puts>:   push   r13
   0x7ffff7a649c2 <_IO_puts+2>: push   r12
   0x7ffff7a649c4 <_IO_puts+4>: mov    r12,rdi
   0x7ffff7a649c7 <_IO_puts+7>: push   rbp
gdb-peda$ set env LD_BIND_NOW=1
gdb-peda$ show env LD_BIND_NOW
LD_BIND_NOW = 1
gdb-peda$ r
Starting program: /home/ubuntu/Dropbox/Workspace/c/doodle/helloworld
[----------------------------------registers-----------------------------------]
RAX: 0x55555555463a (<main>:    push   rbp)
RBX: 0x0
RCX: 0x555555554660 (<__libc_csu_init>: push   r15)
RDX: 0x7fffffffe368 --> 0x7fffffffe615 ("HOME=/home/ubuntu")
RSI: 0x7fffffffe358 --> 0x7fffffffe5e2 ("/home/ubuntu/Dropbox/Workspace/c/doodle/helloworld")
RDI: 0x1
RBP: 0x7fffffffe270 --> 0x555555554660 (<__libc_csu_init>:      push   r15)
RSP: 0x7fffffffe270 --> 0x555555554660 (<__libc_csu_init>:      push   r15)
RIP: 0x55555555463e (<main+4>:  lea    rdi,[rip+0x9f]        # 0x5555555546e4)
R8 : 0x7ffff7dd0d80 --> 0x0
R9 : 0x7ffff7dd0d80 --> 0x0
R10: 0x0
R11: 0x1
R12: 0x555555554530 (<_start>:  xor    ebp,ebp)
R13: 0x7fffffffe350 --> 0x1
R14: 0x0
R15: 0x0
EFLAGS: 0x246 (carry PARITY adjust ZERO sign trap INTERRUPT direction overflow)
[-------------------------------------code-------------------------------------]
   0x555555554635 <frame_dummy+5>:      jmp    0x5555555545a0 <register_tm_clones>
   0x55555555463a <main>:       push   rbp
   0x55555555463b <main+1>:     mov    rbp,rsp
=> 0x55555555463e <main+4>:     lea    rdi,[rip+0x9f]        # 0x5555555546e4
   0x555555554645 <main+11>:    call   0x555555554510 <puts@plt>
   0x55555555464a <main+16>:    mov    eax,0x0
   0x55555555464f <main+21>:    pop    rbp
   0x555555554650 <main+22>:    ret
[------------------------------------stack-------------------------------------]
0000| 0x7fffffffe270 --> 0x555555554660 (<__libc_csu_init>:     push   r15)
0008| 0x7fffffffe278 --> 0x7ffff7a05b97 (<__libc_start_main+231>:       mov    edi,eax)
0016| 0x7fffffffe280 --> 0x1
0024| 0x7fffffffe288 --> 0x7fffffffe358 --> 0x7fffffffe5e2 ("/home/ubuntu/Dropbox/Workspace/c/doodle/helloworld")
0032| 0x7fffffffe290 --> 0x100008000
0040| 0x7fffffffe298 --> 0x55555555463a (<main>:        push   rbp)
0048| 0x7fffffffe2a0 --> 0x0
0056| 0x7fffffffe2a8 --> 0xd117bf73fe78886d
[------------------------------------------------------------------------------]
Legend: code, data, rodata, value

Breakpoint 1, main () at helloworld.c:21
21          printf("Hello world!\n");
gdb-peda$ x/i 0x555555554510
   0x555555554510 <puts@plt>:   jmp    QWORD PTR [rip+0x200aba]        # 0x555555754fd0
gdb-peda$ x/gx 0x555555754fd0
0x555555754fd0: 0x00007ffff7a649c0
gdb-peda$ x/4i 0x00007ffff7a649c0
   0x7ffff7a649c0 <_IO_puts>:   push   r13
   0x7ffff7a649c2 <_IO_puts+2>: push   r12
   0x7ffff7a649c4 <_IO_puts+4>: mov    r12,rdi
   0x7ffff7a649c7 <_IO_puts+7>: push   rbp