How to Check the State of Caps, Num and Scroll Lock Keys on Screen in Ubuntu

I am sure most of us have been through situations where we enter a password, but the system rejects it, repeatedly, and then we realize that it’s our fault as we didn’t notice that the Caps Lock key was on.

If those having a keyboard with LED lights can miss the indication, then think of the users that use a keyboard without lights, not to mention those who type so fast that they don’t even look at their keyboard while typing. Of course, they are more likely to make such mistakes.

Is there a way to avoid such situations? To be fair, nothing can guarantee that a user will not commit such mistakes, but there are some software tools that can bring the frequency down. One such tool is indicator-keyboard-led which we will be discussing in this article.

The indicator-keyboard-led tool is basically a Unity application indicator that is primarily designed for keyboards that do not have the lock key LED lights. What it does is simulate keyboard lock key LEDs on your desktop, essentially displaying their status on your Ubuntu machine’s system tray.

The tool also allows users to toggle the state of the lock keys with mouse clicks, something that could also be really helpful in scenarios where the keyboard starts malfunctioning.

Before we go ahead and explain how to download and install indicator-keyboard-led, let’s first make sure all its dependencies are met. The tool’s official GitHub page lists the following dependencies:

  • Python 3 (*)
  • GTK+ 3 (*)
  • AppIndicator 3 (*)
  • Python 3 GObject introspection (python3-gi)
  • xdotool

Assuming that you are using a recent Ubuntu version (we are focusing on Ubuntu 16.04 anyway), the first three in the list – that are marked with an asterisk – are likely to be already installed on your system. To install the rest run the following command:

sudo apt-get install python3-gi xdotool

Once done, head here to download the tool. You’ll notice that the downloaded file is an archive (in .zip format). Just extract it, and you’ll see a Python script named “” That’s the tool.

To launch the tool just execute the python script using the following command:


The indicator will appear on your system tray.


Now, if you turn on any of these lock keys through the keyboard, the bubble corresponding to it will become white, indicating that the key is on.


If any of these keys is not working on your keyboard, you can toggle it by clicking on the corresponding option in the indicator’s drop-down menu.


You can also cut short the indicator’s appearance – in this case, only the initials will appear on the system tray icon.


But for this you have to launch the tool using the following command:

python3 --short

Similarly, you can change the order of the simulated keys using the --order option in the command. For example, the following command will display the keys in order: Scroll, Num, and Caps.

python3 --order SNC


If you want the tool to skip displaying any particular key, just remove that key’s initial from the value you pass to the --order option. For example, the following command will simulate only the Num and Caps lock keys:

python3 --order NC

Needless to say, indicator-keyboard-led is an extremely useful tool, especially for those whose keyboard does not have lock key lights. Plus, it’s easy to install and use. Given that it’s just a Python script, those with good knowledge of the language can even extend the functionality if they want.

Leave a Reply

Yeah! You've decided to leave a comment. That's fantastic! Check out our comment policy here. Let's have a personal and meaningful conversation.