debug with gdb

$ gdb ./test
Reading symbols from ./test...done.
(gdb) break main
Breakpoint 1 at 0x4005c1
(gdb) run
Starting program: /home/fcuny/workspace/tmp/file/test

Breakpoint 1, 0x00000000004005c1 in main ()
(gdb) disassemble
Dump of assembler code for function main:
   0x00000000004005bd <+0>:     push   %rbp
   0x00000000004005be <+1>:     mov    %rsp,%rbp
=> 0x00000000004005c1 <+4>:     sub    $0x10,%rsp
   0x00000000004005c5 <+8>:     mov    $0x400694,%esi
   0x00000000004005ca <+13>:    mov    $0x400696,%edi
   0x00000000004005cf <+18>:    callq  0x4004b0 <fopen@plt>
   0x00000000004005d4 <+23>:    mov    %rax,-0x8(%rbp)
   0x00000000004005d8 <+27>:    cmpq   $0x0,-0x8(%rbp)
   0x00000000004005dd <+32>:    jne    0x4005f0 <main+51>
   0x00000000004005df <+34>:    mov    $0x4006a1,%edi
   0x00000000004005e4 <+39>:    callq  0x4004c0 <perror@plt>
   0x00000000004005e9 <+44>:    mov    $0x1,%eax
   0x00000000004005ee <+49>:    jmp    0x400601 <main+68>
   0x00000000004005f0 <+51>:    mov    -0x8(%rbp),%rax
   0x00000000004005f4 <+55>:    mov    %rax,%rdi
   0x00000000004005f7 <+58>:    callq  0x400480 <fclose@plt>
   0x00000000004005fc <+63>:    mov    $0x0,%eax
   0x0000000000400601 <+68>:    leaveq
   0x0000000000400602 <+69>:    retq
End of assembler dump.