How to update Ubuntu LTS Enablement Stack

Ubuntu LTS releases, like 14.04 are supported for many years. However, the kernel and X server that ship with them are only updated for minor changes or revisions during this period. Every six months Ubuntu puts out a new point release for its recent LTS, like 14.04.2. This has the kernel and X server from the most recent Ubuntu non-LTS release.

The Ubuntu LTS Enablement Stack provides these updated Linux kernels and X server releases for users running older LTS releases. For computers with NVIDIA graphics cards, I have found that switching to newer kernel and X server has always improved the driver errors I face.

The LTS Enablement Stack webpage has the charts of what kernel and X server versions are available for your LTS release. You can also find the command to update your LTS from there.

For example, I updated my 14.04 system using this command:

$ sudo apt-get install --install-recommends linux-generic-lts-vivid xserver-xorg-core-lts-vivid xserver-xorg-lts-vivid xserver-xorg-video-all-lts-vivid xserver-xorg-input-all-lts-vivid libwayland-egl1-mesa-lts-vivid

My kernel was updated from 3.13 to 3.19 after this. Remember to reboot after this command! 😄

Tried with: Ubuntu 14.04

How to make startup disk from ISO using Startup Disk Creator

You need a startup disk or USB flash drive loaded with Ubuntu to install it on a new computer. Ubuntu can be downloaded as an ISO file. The Startup Disk Creator tool can be used to create such a startup disk from a ISO file.


Startup Disk Creator will be present on a Ubuntu computer. If by chance you do not have it, it can be installed easily:

$ sudo apt install usb-creator-gtk


  1. Download the Ubuntu (or any other) ISO file you need to make a startup disk from.

  2. Insert the USB stick or drive that you want to use as the startup disk. Note that it needs to be in FAT or FAT32 format! (Otherwise Startup Disk Creator will not show this drive.)

  3. Start the Startup Disk Creator from the Dash or usb-creator-gtk from the shell.

  4. Choose the source disk image (the downloaded ISO file) and the disk to use and click Make Startup Disk.

Once it is done, you can use this USB flash drive to install Ubuntu on other computers by booting from this drive! 😃

Note: An alternative to Startup Disk Creator is UNetBootIn, which can be used as described here. I have faced problems using it for making startup USB flash drives of Ubuntu 14.10.

Tried with: Startup Disk Creator 0.2.56 and Ubuntu 14.04

The disappearing clock in the Panel


I restarted Ubuntu. After the restart and logging in I discover that the Clock in the Panel is missing! I check and see that the package indicator-datetime is still installed. I open System Settings and go to Time and Date and see that everything in the Clock tab is disabled, so I cannot change it.


This is a bug in Unity as described here. It is supposedly happening due to a configuration value being reset after packages are upgraded.

Anyway, the only solution that works right now is to kill and restart the Panel service:

$ killall unity-panel-service

This worked for me and my clock was back in the Panel! 🙂

Tried with: Ubuntu 14.04

How to list PPA repositories

The Y PPA Manager is a GUI that can be used to view, add or remove PPA repositories in Ubuntu. If you prefer the shell, the add-apt-repository program can be used to add or remove PPA repositories. However, there is no program that lists the PPA repositories you have added to your system.

Here is a popular shell script that lists PPA repositories:

Tried with: Ubuntu 14.04

How to use Synergy in Ubuntu


Synergy is a tool that can be used to share a keyboard and mouse across multiple computers. In this post, I will describe how I used Synergy to share a keyboard and mouse between two computers running Ubuntu.


  • Server is the computer whose keyboard and mouse you want to always use.

  • Client is the computer whose display you want to control using the server’s keyboard and mouse.

  • Make sure the server and client are connected on the same wireless network or LAN. Make sure you can ping the server from the client and the client from the server.

  • Install Synergy on both the server and the client computers:

$ sudo apt install synergy

Setup the server

  • Type Synergy in the Dash or synergy at the shell to open the GUI of Synergy.

  • Choose the Server option. Choose an encryption method from the dropdown and provide a password.

  • In the main dialog, make sure Configure interactively is chosen.

  • Click on Configure server. In the Screens and links tab, you should be able to see a blue display, which represents the server. Drag down the blue display (in the top-right corner) to a box neighboring the server display. This new display you added represents the client. My client display on my desk is to the left of my server, so I dragged the blue display and placed it to the left of the server display.

  • Double-click on the display you added. In the Screen Settings dialog, provide a Screen name to the client. This can be anything, it is just used in the grid of displays. Add an alias: you have to give the hostname or IP address of the client here.

  • Click Start to start the server. It will minimize to the system tray at the top.

Setup the client

  • Type Synergy in the Dash or synergy at the shell to open the GUI of Synergy.

  • Choose the Client option. Choose the encryption method from the dropdown and password that you had used on the server. They have to be the same!

  • In the main dialog, type in the IP address of the server and press Start. Your client is now connected to the server! 🙂


  • Remember that I have placed my client to the left of the server in the grid. So, when I want to switch to my client display, I hit the mouse to the left side of the display on my server. It will appear in the client! All the keys I type on the server keyboard now appear in the client. To switch back, hit the mouse to the right side of the client display.

Tried with: Synergy 1.4.12 and Ubuntu 14.04

How to suspend in Ubuntu

You can suspend your notebook running Ubuntu by clicking the Gear icon and choosing Suspend. If you want to suspend from the shell, then the relevant command as described here is:

dbus-send --system --print-reply --dest=org.freedesktop.login1 /org/freedesktop/login1 "org.freedesktop.login1.Manager.Suspend" boolean:true

If you use this frequently, then you can turn it into a script or create a keyboard shortcut for it.

Note: The other methods suggested on the web which use the powermanagement-interface did not work for me on Ubuntu 14.04.

Brightness Indicator for Ubuntu


The brightness of notebook displays can be easily adjusted by pressing special key combinations on its keyboard. On some notebooks, these special keys may not work in Ubuntu, especially after returning from a hibernation or suspend. If you face such scenario, then you can use the Brightness Indicator application for Ubuntu.

Installing it is easy:

$ sudo add-apt-repository ppa:indicator-brightness/ppa
$ sudo apt-get update
$ sudo apt install indicator-brightness

To start it, look for Brightness indicator in the Dash. I found that on my notebook it gave 18 levels of brightness (0-17).

Tried with: Brightness Indicator 0.4 and Ubuntu 14.04

How to install CUDA 6.5 on Ubuntu 14.04

Installing CUDA is becoming increasingly easier on Ubuntu. I think I keep hitting problems because I am usually updating from an older NVIDIA graphics driver or CUDA version. NVIDIA continues to be quite bad at providing error-free upgrades. Anyway, this is what worked for me:

  • Do not try to install any of the NVIDIA drivers or CUDA packages that are in the Ubuntu repositories. I wasted a day with the errors these operations threw up!

  • Uninstall all CUDA packages and NVIDIA drivers you may have on your Ubuntu system.

  • Download the CUDA .deb package for Ubuntu 14.04 from here. For me, it was a cuda-repo-ubuntu1404_6.5-14_amd64.deb file.

  • The .deb file just adds a CUDA repository maintained by NVIDIA. Install this .deb file and update:

$ sudo gdebi cuda-repo-ubuntu1404_6.5-14_amd64.deb
$ sudo apt-get update
  • Installing CUDA now is easy as this:
$ sudo apt-get install cuda

This is a big install, it will install everything including a nvidia-340 driver that actually worked and NVIDIA NSight. After the install, reboot the computer. Your CUDA is ready for work now 🙂

Note: I tried this on two systems. On one, it installed without any problem. On the other, it gave an error of unmet dependencies. I have described here how I solved this problem.

Tried with: NVIDIA GeForce GTS 250 and NVIDIA GTX Titan

Ubuntu guest in VirtualBox loses network access after Windows host hibernate


I have a Windows host system which is running an Ubuntu guest inside VirtualBox. While the Ubuntu guest is running, I hibernate the Windows host. Later, after the Windows host is resumed, I find that network connectivity is lost in the Ubuntu guest. The LAN network interface is present and shows as connected. However, no domain name can be resolved or pinged.


I found that this bug in VirtualBox is reported here. Disconnecting the network interface and connecting back did not work. But, turning off networking and turning it back on worked!

Tried with: Ubuntu 14.04, VirtualBox 4.3.20 and Windows 7 Professional 64-bit

How to switch virtual console on Ubuntu inside VirtualBox

I sometimes run Ubuntu inside a VirtualBox virtual machine. In this Ubuntu, to switch from graphical window manager to the first virtual console, press Host + F1. By default, the Host key in VirtualBox is assigned to Right Ctrl key. So, I press Right Ctrl + F1. To get back to graphical window manager, switch to the 7th virtual console: Right Ctrl + F7.

Tried with: VirtualBox 4.3.20