[root@localhost ~]# cat .s

 .file "write.s"

 .section .rodata

          hello: .string "hello, world!\n"

 .section .text

 .global _start

 _start:

 movl $,     %eax  # syscall number for write function

 movl $,     %ebx  #  standand for stdout

 movl $hello, %ecx  # the second argument of write function

 movl $,    %edx  # the third argument of write function

 int  $0x80         # interrupt to call write

 movl $,     %eax  # syscall number for sys_exit function

 xorl %ebx,   %ebx  # the argument for sys_exit function

 int  $0x80         # interrupt to call sys_exit

 ret                # return to the caller of the function

Usage: objdump <option(s)> <file(s)>

 Display information from object <file(s)>.

 At least one of the following switches must be given:

  -a, --archive-headers    Display archive header information

  -f, --file-headers       Display the contents of the overall file header

  -p, --private-headers    Display object format specific file header contents

  -h, --[section-]headers  Display the contents of the section headers

  -x, --all-headers        Display the contents of all headers

  -d, --disassemble        Display assembler contents of executable sections

  -D, --disassemble-all    Display assembler contents of all sections

  -S, --source             Intermix source code with disassembly

  -s, --full-contents      Display the full contents of all sections requested

  -g, --debugging          Display debug information in object file

  -e, --debugging-tags     Display debug information using ctags style

  -G, --stabs              Display (in raw form) any STABS info in the file

  -W, --dwarf              Display DWARF info in the file

  -t, --syms               Display the contents of the symbol table(s)

  -T, --dynamic-syms       Display the contents of the dynamic symbol table

  -r, --reloc              Display the relocation entries in the file

  -R, --dynamic-reloc      Display the dynamic relocation entries in the file

  @<file>                  Read options from <file>

  -v, --version            Display this program's version number

  -i, --info               List object formats and architectures supported

  -H, --help               Display this information

[root@localhost ~]# objdump -D ./.o

./.o:     file format elf64-x86-

Disassembly of section .text:

 <_start>:

   :   b8              mov    $0x4,%eax

   :   bb              mov    $0x1,%ebx

   a:   b9              mov    $0x0,%ecx

   f:   ba 0e             mov    $0xe,%edx

  :   cd                    int    $0x80

  :   b8              mov    $0x1,%eax

  1b:    db                   xor    %ebx,%ebx

  1d:   cd                    int    $0x80

  1f:   c3                      retq

Disassembly of section .rodata:

 <hello>:

   :     6c 6c 6f          pushq  $0x6f6c6c65

   :   2c                    sub    $0x20,%al

   :    6f                   ja      <_start+0x78>

   :    6c                   jb      <_start+0x77>

   b:     0a                and    %ecx,%fs:(%rdx)

        ...