$ gdb -x .gdbinit ... # run gdb with .gdbinit
    (gdb) b foo  # set breakpoint to function `foo'
    (gdb) run    # execute debuggee program
    ...          # and stop at break point
    (gdb) trace_machine_instructions
    ...          # continue program and show each instructions
    ...          # all output will be saved on 'gdb.txt'

  $ gdb -x ../clean-trunk/.gdbinit --args ./miniruby ../clean-trunk/benchmark/bm_app_fib.rb
  GNU gdb (GDB) 7.0.1-debian
  Copyright (C) 2009 Free Software Foundation, Inc.
  License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
  This is free software: you are free to change and redistribute it.
  There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
  and "show warranty" for details.
  This GDB was configured as "i486-linux-gnu".
  For bug reporting instructions, please see:
  <http://www.gnu.org/software/gdb/bugs/>...
  Reading symbols from /home/ko1/build/ruby/clean-build/miniruby...done.
  (gdb)
  (gdb) b vm_exec
  Breakpoint 1 at 0x81c4c00: file ../clean-trunk/vm.c, line 1116.
  (gdb) run
  Starting program: /home/ko1/build/ruby/clean-build/miniruby ../clean-trunk/benchmark/bm_app_fib.rb
  [Thread debugging using libthread_db enabled]
  [New Thread 0xb7c80b70 (LWP 7878)]
  
  Breakpoint 1, vm_exec (th=0x8264b88) at ../clean-trunk/vm.c:1116
  1116    {
  (gdb) continue
  Continuing.
  
  Breakpoint 1, vm_exec (th=0x8264b88) at ../clean-trunk/vm.c:1116
  1116    {
  (gdb) (gdb) trace_machine_instructions
  Line 1116 of "../clean-trunk/vm.c" starts at address 0x81c4c00 <vm_exec> and ends at 0x81c4c01 <vm_exec+1>.
  1122        TH_PUSH_TAG(th);
  1: x/i $pc
  0x81c4c01 <vm_exec+1>:  mov    %eax,%edx
  Line 1122 of "../clean-trunk/vm.c" starts at address 0x81c4c01 <vm_exec+1> and ends at 0x81c4c03 <vm_exec+3>.
  1116    {
  1: x/i $pc
  0x81c4c03 <vm_exec+3>:  mov    %esp,%ebp
  Line 1116 of "../clean-trunk/vm.c" starts at address 0x81c4c03 <vm_exec+3> and ends at 0x81c4c19 <vm_exec+25>.
  0x081c4c05      1116    {
  1: x/i $pc
  0x81c4c05 <vm_exec+5>:  push   %edi
  Line 1116 of "../clean-trunk/vm.c" starts at address 0x81c4c03 <vm_exec+3> and ends at 0x81c4c19 <vm_exec+25>.
  0x081c4c06      1116    {
  1: x/i $pc
  0x81c4c06 <vm_exec+6>:  push   %esi
  Line 1116 of "../clean-trunk/vm.c" starts at address 0x81c4c03 <vm_exec+3> and ends at 0x81c4c19 <vm_exec+25>.
  0x081c4c07      1116    {
  1: x/i $pc
  0x81c4c07 <vm_exec+7>:  push   %ebx
  Line 1116 of "../clean-trunk/vm.c" starts at address 0x81c4c03 <vm_exec+3> and ends at 0x81c4c19 <vm_exec+25>.
  0x081c4c08      1116    {
  1: x/i $pc
  0x81c4c08 <vm_exec+8>:  sub    $0x15c,%esp
  Line 1116 of "../clean-trunk/vm.c" starts at address 0x81c4c03 <vm_exec+3> and ends at 0x81c4c19 <vm_exec+25>.
  0x081c4c0e      1116    {
  ...
  (gdb) quit

  vm_exec+1                 mov    %eax,%edx                                   ../clean-trunk/vm.c:1122
  vm_exec+3                 mov    %esp,%ebp                                   ../clean-trunk/vm.c:1116
  vm_exec+5                 push   %edi                                        ../clean-trunk/vm.c:1116
  vm_exec+6                 push   %esi                                        ../clean-trunk/vm.c:1116
  vm_exec+7                 push   %ebx                                        ../clean-trunk/vm.c:1116
  vm_exec+8                 sub    $0x15c,%esp                                 ../clean-trunk/vm.c:1116
  vm_exec+14                call   0x805c3c0 <__i686.get_pc_thunk.bx>          ../clean-trunk/vm.c:1116
  __i686.get_pc_thunk.bx    mov    (%esp),%ebx                                 
  __i686.get_pc_thunk.bx+3  ret                                                
  vm_exec+19                add    $0x8dd1d,%ebx                               ../clean-trunk/vm.c:1116
  vm_exec+25                mov    %eax,-0xcc(%ebp)                            ../clean-trunk/vm.c:1116
  ...