大家好，我安装了ubuntu14.04,图形界面可以正常使用，但是命令行界面是黑屏，f1到f6都是黑屏，请问这种情况可能是什么原因造成的？该如何处理？谢谢！

刚安装的？有无使用私有显卡驱动？
可以尝试 编辑 /etc/default/grub 添加

(注意行首不能有#)
保存，运行 sudo update-grub
重新启动计算机

若仍无效，尝试在 /etc/default/grub 中设置 GRUB_GFXMODE
例如 较低分辨率 GRUB_GFXMODE=640x480
或原生分辨率 例如 GRUB_GFXMODE=1366x768
保存后 运行 sudo update-grub
重新启动计算机

参考
http://askubuntu.com/questions/162535/why-does-switching-to-the-tty-give-me-a-blank-screen
http://askubuntu.com/questions/43386/how-do-i-get-my-blacked-out-ttys-back
http://unix.stackexchange.com/questions/157111/why-are-my-virtual-consoles-completely-blank

没有安装私有显卡驱动，需要安装吗？

刚刚试了一下，文件是只读的没法更改，我进不了命令行也没法进root权限。。。。

你进不了命令行不是还有图形界面么，
在图形界面下面改啊
Ctrl + Alt + T

sudo 提权，gedit 是ubuntu 自带的文本编辑器

1. 某些顯卡品牌/型號 驅動模組 的 Bug 可能造成這個情形
是不是 這個原因
要先看看 顯卡品牌/型號 及 作用中的驅動 再查一查 相關已知 Bug Reports
把下面指令 複製 貼進終端機 執行
1-1. uname -a
1-2. sudo lspci -knn
1-3. sudo lshw -numeric -class video
1-4. sudo ubuntu-drivers devices
把結果直接 選取/複製 貼上來

结果是这样的：

Linux dcsds1-F3Sc 3.13.0-32-generic #57-Ubuntu SMP Tue Jul 15 03:51:08 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
dcsds1@dcsds1-F3Sc:~$ sudo lspci -knn
00:00.0 Host bridge [0600]: Intel Corporation Mobile PM965/GM965/GL960 Memory Controller Hub [8086:2a00] (rev 03)
Subsystem: ASUSTeK Computer Inc. Device [1043:14e7]
00:01.0 PCI bridge [0604]: Intel Corporation Mobile PM965/GM965/GL960 PCI Express Root Port [8086:2a01] (rev 03)
Kernel driver in use: pcieport
00:1a.0 USB controller [0c03]: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #4 [8086:2834] (rev 03)
Subsystem: ASUSTeK Computer Inc. Device [1043:14e7]
Kernel driver in use: uhci_hcd
00:1a.1 USB controller [0c03]: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #5 [8086:2835] (rev 03)
Subsystem: ASUSTeK Computer Inc. Device [1043:14e7]
Kernel driver in use: uhci_hcd
00:1a.7 USB controller [0c03]: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #2 [8086:283a] (rev 03)
Subsystem: ASUSTeK Computer Inc. Device [1043:14e7]
Kernel driver in use: ehci-pci
00:1b.0 Audio device [0403]: Intel Corporation 82801H (ICH8 Family) HD Audio Controller [8086:284b] (rev 03)
Subsystem: ASUSTeK Computer Inc. Asus M51S series [1043:1339]
Kernel driver in use: snd_hda_intel
00:1c.0 PCI bridge [0604]: Intel Corporation 82801H (ICH8 Family) PCI Express Port 1 [8086:283f] (rev 03)
Kernel driver in use: pcieport
00:1c.1 PCI bridge [0604]: Intel Corporation 82801H (ICH8 Family) PCI Express Port 2 [8086:2841] (rev 03)
Kernel driver in use: pcieport
00:1c.2 PCI bridge [0604]: Intel Corporation 82801H (ICH8 Family) PCI Express Port 3 [8086:2843] (rev 03)
Kernel driver in use: pcieport
00:1c.3 PCI bridge [0604]: Intel Corporation 82801H (ICH8 Family) PCI Express Port 4 [8086:2845] (rev 03)
Kernel driver in use: pcieport
00:1c.4 PCI bridge [0604]: Intel Corporation 82801H (ICH8 Family) PCI Express Port 5 [8086:2847] (rev 03)
Kernel driver in use: pcieport
00:1c.5 PCI bridge [0604]: Intel Corporation 82801H (ICH8 Family) PCI Express Port 6 [8086:2849] (rev 03)
Kernel driver in use: pcieport
00:1d.0 USB controller [0c03]: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #1 [8086:2830] (rev 03)
Subsystem: ASUSTeK Computer Inc. Device [1043:14e7]
Kernel driver in use: uhci_hcd
00:1d.1 USB controller [0c03]: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #2 [8086:2831] (rev 03)
Subsystem: ASUSTeK Computer Inc. Device [1043:14e7]
Kernel driver in use: uhci_hcd
00:1d.2 USB controller [0c03]: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #3 [8086:2832] (rev 03)
Subsystem: ASUSTeK Computer Inc. Device [1043:14e7]
Kernel driver in use: uhci_hcd
00:1d.7 USB controller [0c03]: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #1 [8086:2836] (rev 03)
Subsystem: ASUSTeK Computer Inc. Device [1043:14e7]
Kernel driver in use: ehci-pci
00:1e.0 PCI bridge [0604]: Intel Corporation 82801 Mobile PCI Bridge [8086:2448] (rev f3)
00:1f.0 ISA bridge [0601]: Intel Corporation 82801HM (ICH8M) LPC Interface Controller [8086:2815] (rev 03)
Subsystem: ASUSTeK Computer Inc. Device [1043:14e7]
Kernel driver in use: lpc_ich
00:1f.1 IDE interface [0101]: Intel Corporation 82801HM/HEM (ICH8M/ICH8M-E) IDE Controller [8086:2850] (rev 03)
Subsystem: ASUSTeK Computer Inc. Device [1043:14e7]
Kernel driver in use: ata_piix
00:1f.2 SATA controller [0106]: Intel Corporation 82801HM/HEM (ICH8M/ICH8M-E) SATA Controller [AHCI mode] [8086:2829] (rev 03)
Subsystem: ASUSTeK Computer Inc. Device [1043:14e7]
Kernel driver in use: ahci
01:00.0 VGA compatible controller [0300]: NVIDIA Corporation G86M [GeForce 8400M G] [10de:0428] (rev a1)
Subsystem: ASUSTeK Computer Inc. Device [1043:1513]
02:00.0 Ethernet controller [0200]: Qualcomm Atheros Attansic L1 Gigabit Ethernet [1969:1048] (rev b0)
Subsystem: ASUSTeK Computer Inc. Device [1043:14e5]
Kernel driver in use: atl1
03:00.0 Network controller [0280]: Intel Corporation PRO/Wireless 3945ABG [Golan] Network Connection [8086:4222] (rev 02)
Subsystem: Intel Corporation Device [8086:1002]
Kernel driver in use: iwl3945
09:01.0 FireWire (IEEE 1394) [0c00]: Ricoh Co Ltd R5C832 IEEE 1394 Controller [1180:0832] (rev 05)
Subsystem: ASUSTeK Computer Inc. Device [1043:14e7]
Kernel driver in use: firewire_ohci
09:01.1 SD Host controller [0805]: Ricoh Co Ltd R5C822 SD/SDIO/MMC/MS/MSPro Host Adapter [1180:0822] (rev 22)
Subsystem: ASUSTeK Computer Inc. Device [1043:14e7]
Kernel driver in use: sdhci-pci
09:01.2 System peripheral [0880]: Ricoh Co Ltd R5C592 Memory Stick Bus Host Adapter [1180:0592] (rev 12)
Subsystem: ASUSTeK Computer Inc. Device [1043:14e7]
Kernel driver in use: r592
09:01.3 System peripheral [0880]: Ricoh Co Ltd xD-Picture Card Controller [1180:0852] (rev 12)
Subsystem: ASUSTeK Computer Inc. Device [1043:14e7]
Kernel driver in use: r852
dcsds1@dcsds1-F3Sc:~$ sudo lshw -numeric -class video
*-display UNCLAIMED
description: VGA compatible controller
product: G86M [GeForce 8400M G] [10DE:428]
vendor: NVIDIA Corporation [10DE]
physical id: 0
bus info: pci@0000:01:00.0
version: a1
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress vga_controller cap_list
configuration: latency=0
resources: memory:fd000000-fdffffff memory:c0000000-cfffffff memory:fa000000-fbffffff ioport:bc00(size=128) memory:fcfe0000-fcffffff
dcsds1@dcsds1-F3Sc:~$ sudo ubuntu-drivers devices
== /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0 ==
vendor : NVIDIA Corporation
modalias : pci:v000010DEd00000428sv00001043sd00001513bc03sc00i00
model : G86M [GeForce 8400M G]
driver : nvidia-304 - distro non-free
driver : nvidia-173 - distro non-free
driver : nvidia-340 - distro non-free recommended
driver : xserver-xorg-video-nouveau - distro free builtin
driver : nvidia-304-updates - distro non-free
driver : nvidia-340-updates - distro non-free

1. 表示沒有合適的顯卡驅動 作用中

3. 猜測 還沒有安裝/設定/啟用 nvidia-340

4. 參閱
https://help.ubuntu.com/community/Binar ... wto/Nvidia
nvidia-graphics-drivers-340

你好，请问这样是说明已经有驱动安装了吗？
dcsds1@dcsds1-F3Sc:~$ glxinfo|head
name of display: :0
display: :0 screen: 0
direct rendering: Yes
server glx vendor string: SGI
server glx version string: 1.4
server glx extensions:
GLX_ARB_multisample, GLX_EXT_import_context, GLX_EXT_texture_from_pixmap,
GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_MESA_copy_sub_buffer,
GLX_OML_swap_method, GLX_SGIS_multisample, GLX_SGIX_fbconfig,
GLX_SGIX_pbuffer, GLX_SGI_make_current_read

如果再安装nvidia-340,可以直接在ubuntu软件中心下载安装吗？谢谢！

1. http://dri.freedesktop.org/wiki/glxinfo/
glxinfo is a command-line tool that can help you diagnose problems with your 3D acceleration setup. It can also provide additional helpful information for developers.
1-1. glxinfo 只能顯示 效能如何 無法區分 驅動種類及版本

2. 把下面指令 複製 貼進終端機 執行 可以精確查出目前作用中的閉源驅動版本
nvidia-settings --glxinfo | grep "OpenGL version string"
結果例子
OpenGL version string: 3.3.0 NVIDIA 340.96
2-1. 上述指令 需要已經安裝 閉源驅動以後 才有

3. 安裝 nvidia-340 或 nvidia-340-updates 都行
3-1. 安裝方法 參考
https://help.ubuntu.com/community/Binar ... stallation
3-2. 建議 整篇都看看
https://help.ubuntu.com/community/Binar ... wto/Nvidia

谢谢！我根据所给链接安装了nvidia-340，但是重启后出现黑屏，屏幕左上角有光标在闪，链接中并没有这种问题的解决方式，请问您是否知道如何解决这种问题？谢谢！

參閱
http://apexu.com/apexu/tw/modules/publi ... ?itemid=14
如何 增加 acpi_osi=linux 及 nomodeset 參數
那一組 核心參數 可能一個 兩個 三個 ...
需要嘗試中挑選

目的 幫你登入桌面 作必要的檢驗跟微調

可以順利登入時 請再貼文

按照链接中的说明进行了修改，仍然无法进入桌面，于是重装了系统，按照二楼三个链接中的方法进行了修改，最后成功了。
谢谢！

成功了，谢谢！