如题：
     文件路径：/etc/X11/xorg.conf

文件内容:
  # nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings:  version 1.0  (mockbuild@builder.wilsonet.com)  Wed Apr 28 18:27:01 EDT 2010

# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig:  version 1.0  (mockbuild@)  Sun Feb 28 14:49:02 EST 2010
### Touch Configuration Beginning ###
### Touch Configuration End ###

Section "ServerLayout"

    InputDevice    "EETI" "SendCoreEvents"
    Identifier     "Layout0"
    Screen      0  "Screen0" 0 0
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
    Option         "Xinerama" "0"
EndSection

Section "Files"
    FontPath        "/usr/share/fonts/default/Type1"
EndSection

Section "InputDevice"

    # generated from default
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Device" "/dev/input/mice"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"

    # generated from data in "/etc/sysconfig/keyboard"
    Identifier     "Keyboard0"
    Driver         "kbd"
    Option         "XkbLayout" "us"
    Option         "XkbModel" "pc105"
EndSection

Section "InputDevice"
    Identifier     "EETI"
    Driver         "egalax"
    Option         "Device" "/dev/ttyS2"
    Option         "Parameters" "/var/lib/eeti.param"
    Option         "ScreenNo" "0"
EndSection

Section "Monitor"
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "Envision EFT7x0 Series"
    HorizSync       30.0 - 72.0
    VertRefresh     50.0 - 160.0
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "ION"
    Option         "Nologo" "TRUE"
EndSection

Section "Screen"

# Removed Option "metamodes" "CRT: nvidia-auto-select +0+0, DFP: nvidia-auto-select +1024+0"
# Removed Option "metamodes" "CRT: nvidia-auto-select +0+0, DFP: 1024x768 +1024+0"
# Removed Option "metamodes" "CRT: nvidia-auto-select +0+0, DFP: 1280x720 +1024+0"
# Removed Option "metamodes" "CRT: nvidia-auto-select +0+0, DFP: NULL"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "TwinView" "1"
    Option         "TwinViewXineramaInfoOrder" "CRT-0"
    Option         "metamodes" "CRT: 1024x768 +0+0, DFP: 1024x768 +1024+0" //修改这行。
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

原来的内容是什么 修改成什么？
使用sed 先匹配 再替换