Lock-down pro-tip to save the battery of your car

Most cars (if not all) consume energy even when they are parked, with the engine off and no visible systems working. Electrical systems including the clock and on-board computer systems drain the battery little by little until they completely empty it.

When the energy level in a battery is low, it might prevent it from being capable to start your car and you will need a boost to get your car running again. In worse scenarios, batteries that are completely drained can get damaged and they need to be replaced.

Therefore, if you do not move your car for a long period (like during the lock-down period), then the extended lack of use might damage the battery and cause it to need replacement.

Simple Solution

Check the operation manual of your car or contact your dealer prior to disconnecting the battery. (We are not sure if there is a car out there that would not like having its battery removed)

Disconnect the battery from you car to stop the energy draining.
To do so remove the cable from the negative port (has the minus sign "-" and is usually black colored).

Do not let the negative and positive cable exposed metal ends touch under any circumstances.

Ubuntu: Headless wireshark (or wireshark from terminal)

Recently, we wanted to use wireshark on an Ubuntu through ssh and no X-Server forwarding enabled.
After a quick search we found tshark.

TShark is a network protocol analyzer. It lets you capture packet data from a live network, or read packets from a previously saved capture file, either printing a decoded form of those packets to the standard output or writing the packets to a file. TShark‘s native capture file format is pcap format, which is also the format used by tcpdump and various other tools.
Without any options set, TShark will work much like tcpdump. It will use the pcap library to capture traffic from the first available network interface and displays a summary line on stdout for each received packet.
TShark is able to detect, read and write the same capture files that are supported by Wireshark.

From: man tshark

Install tshark on Ubuntu

sudo apt-get install tshark -y;

Using tshark to capture all traffic on eth0 to a pcap file

sudo tshark -i eth0 -w something.pcap;

Note: If you just want to capture network traffic on a network interface and not use the additional features wireshark has to offer, you can also use tcpdumpas follows

#The following command will create a files that has in its name the current date and time using the date function.
sudo tcpdump -i eth0 -w "data.`date +%Y-%m-%d\ %H.%M`.pcap";

Send ALT+CTRL+Delete to QEMU virtual machine 1

Recently we wanted to start a Windows virtual machine from a physical hard disk using a Fedora w/ GNOME 3 host machine to change the domain password of a user.
To do so, we used QEMU, QEMU is a generic and open source machine emulator and virtualizer.

To perform the password change, we needed to sent the ALT+CTRL+Delete key combination to the virtual machine to access the system screen and then change the user password.
Pressing ALT+CTRL+Delete on the Fedora/GNOME 3 host machine, it popped up a prompt to shut down the host machine instead of sending the key combination to the active window of the VM. Apparently, we could not sent the key combination directly to the VM and had to find a way around it.


We pressed ALT+CTRL+2 while the QEMU window was selected/active to switch to the QEMU terminal/monitor.
In the blank screen that appeared, we typed sendkey alt-ctrl-delete and pressed the Enter key.
This action sent to the virtual machine OS the key combination ALT+CTRL+Delete.
Finally, to switch back  to the guest screen we pressed ALT+CTRL+1.

HOWTO: Make Terminator Terminal Act Like Guake Terminal in Ubuntu 16.04 LTS (The easy ways) 3

First way to make terminator toggle its visibility using the F12 key (like guake)

  • Start terminator
  • Right click anywhere in the terminal area and click on the Preferences option


  • In the new window, click on the Keybindings tab and scroll down until you find the line that has the following information:
    Name : hide_window
    Action : Toggle window visibility


  • Click on the Keybinding column (3rd column), the value will change to New accelerator..., hit the key combination you want to be used to toggle the visibility of terminator. If you want the same behavior as guake, hit F12. You will see that the value in the Keybinding column will change to F12.
  • Hit the close button to close the settings window.
  • In the terminal try the key you just set (e.g F12) to see if it works. If it doesn’t work and in the case of F12 writes on the terminal a ~, close terminator and re-open it for the changes to get applied.

Second way to make terminator toggle its visibility using the F12 key (like guake)

  • Create the folder tree ~/.config/terminator (maybe it exists already). Please note that the . in front of config is purposely there, it is the way to hide a folder.
  • In the folder create a file named config (the full path would be ~/.config/terminator/config) and put the following as content:
  hide_window = F12
      parent = window0
      type = Terminal
      parent = ""
      type = Window
  • Save the file and start terminator, pressing the F12 key should hide the terminal, pressing it once more should make it reappear.

HOWTO: Make Terminator Terminal Act Like Guake Terminal in Ubuntu 16.04 LTS (XenialXerus) Desktop edition x64 bit architecture 3

We propose an alternative solution to making terminator act like guake that requires two additional packages: xdotool and wmctrl.

Our proposal will launch terminator if there is not instance running.

In Ubuntu you can install the needed packages from the official repositories using sudo apt-get install xdotool wmctrl.

Using a text editor, create in you home folder a file named nano ~/toggle_visibility.sh and copy there the contents of the following chunk of code. You can also use nano, from a terminal issue nano ~/toggle_visibility.sh, then paste the code and hit CTRL+X to exit. When prompted if you want to save press ‘Y’ and hit enter.


#The purpose of this script is to allow the user to toggle the visibility of (almost) any window.
#Please note it will work on the first match, so if there are multiple instances of an application it would be a random window of them the one to be affected.
#Usually it will control the window with the smallest PID.

#Checking that all dependencies are met, since we cannot proceed without them.
declare -a DEPENDENCIES=("xdotool" "wmctrl");
declare -a MANAGERS=("dnf" "apt-get");

    echo -n "Checking if $DEPENDENCY is available";
    if hash $DEPENDENCY 2>/dev/null; then
        echo "- OK, Found";
        echo "- ERROR, Not Found in $PATH";
        for MANAGER in ${MANAGERS[@]}; do
            if hash $MANAGER 2>/dev/null; then
                echo -n "$DEPENDENCY is missing, would you like to try and install it via $MANAGER now? [Y/N] (default is Y): ";
                read ANSWER;
                if [[ "$ANSWER" == "Y" || "$ANSWER" == "y" || "$ANSWER" == "" ]]; then
                    sudo "$MANAGER" install "$DEPENDENCY";
                    echo "Terminating";
                    exit -1;


#Checking if the application name provided by the user exists
if ! hash $APPLICATION 2>/dev/null; then
    echo -e "$APPLICATION does not seem to be a valid executable\nTerminating";
    exit -2;

#Checking if the application is running.
PID=$(pgrep -u `whoami` -f "$FULL_COMMAND" | head -n 1);

#If the application is not running, we will try to launch it.
if [ -z $PID ]; then
  echo "$FULL_COMMAND not running, launching it..";
    #Since the application has a live instance, we can proceed with the rest of the code.
    #We will get the PID of the application that is currently focused, if it is not the application we passed as parameter we will change the focus to that. In the other case, we will minimize the application.
  echo -n "$FULL_COMMAND instance found - ";
    FOCUSED=$(xdotool getactivewindow getwindowpid);
    if [[ $PID == $FOCUSED ]]; then
    echo "It was focused so we are minimizing it";
        #We minimize the active window which we know in this case that it is the application we passed as parameter.
        xdotool getactivewindow windowminimize;
    echo "We are setting the focus on it";
        #We set the focus to the application we passed as parameter. If it is minimized it will be raised as well.
        wmctrl -x -R $APPLICATION;

exit 0

Afterwards, you need to make the script an executable so you should issue chmod +x ~/toggle_visibility.sh to do that.

Then, execute ~/toggle_visibility.sh in your terminal once. We need to do that in order to install any missing dependencies for the tool.

Finally, you need to create a custom shortcut that will call the script using the key combination you like at any point.

To complete the procedure:

  1. Go to ‘System Settings’ either by clicking on the menu on the top right corner that looks like a light bulb or by issuing the following in a terminal unity-control-center to start the unity control center.
  2. In the newly appeared window, click on the ‘keyboard’ icon that is in the category ‘Hardware’.
  3. After that, click on the tab ‘Shortcuts’
  4. and on the left list, click on custom shortcuts.
  5. You will see a button with the + sign right next to the list, click that.
  6. In the dialog box that will appear enter the following:
    – In the name field enter anything you like. e.g ‘Toggle Terminator Visibility’
    – In the command field enter /home/<USER>/toggle_visibility.sh terminator "^/usr/bin/python /usr/bin/terminator$" where <USER> enter your own username.
    – Click apply.
  7. You will see a new row with two columns with the name you just set in the first column. Click on the second column, where it should say ‘Disabled’ and the press the key combination you want for toggling terminator e.g F12

You are ready to go 🙂

Just try the key combination you just provided and terminator will appear in front of you. Pressing it once more it will hide it.

NOTE: Please keep in mind that the above script can be used for other applications as well. In step 7, we gave as parameter the name of the application to be used, if you change that you could use it with other applications like Firefox.