Objdump

objdump is a tool to work with binary object files. It is part of the GNU binutils.

objdump can be used for disassembly, with the -d flag, eg.

 objdump -d executable

If the executable has been compiled with debugging information, the -S flag will intermix source and disassembled code.

The --syms flag shows symbol information.

Example

• Have a file main.cpp:

#include <iostream>
int main()
{
  std::cout << "hello world" << std::endl;
}

• Build it:

g++ main.cpp

• disassemble it:

objdump -d a.out

• show only the first lines:

objdump -d a.out | head
[...]
0000000000400718 <_init>:
  400718:       48 83 ec 08             sub    $0x8,%rsp
  40071c:       e8 cb 00 00 00          callq  4007ec <call_gmon_start>
[...]

• use another debugger format:

objdump -M intel -d a.out | head 
[...]
0000000000400718 <_init>:
  400718:       48 83 ec 08             sub    rsp,0x8
  40071c:       e8 cb 00 00 00          call   4007ec <call_gmon_start>
[...]

See also

• programming-related commands
• ldd
• nm
• gdb