https://www.howtogeek.com/274587/how-to-get-a-notification-when-caps-lock-or-num-lock-is-enabled-in-ubuntu/
I have a Logitec K235 wireless keyboard for using with my notebook computer and it is a great keyboard but there are no indicator LED's to show when a Caps Lock or Num Lock key has been pressed.
I have had numerous times where I have accidentally hit the Caps Lock key and then when I go to enter a password to access a web site, I get a "wrong password" error from the website. I spend many minutes trying to figure out why my password is not correct, until I finally realize that the Cap key has been accidentally pressed.
The above article, provides instructions on how to install a small program that will pop up a notice, at the top of my screen, alerting me that the Caps Lock is on or off, when I press the Cap Locks key. It also works for the Num Lock key.
This program works with my Mint 19.1 notebook computer. What a great program. I am a happy camper, now. :-)
I used to resort to searching out a text document on my computer and add some type to the document, to see if the Caps Key was pressed. :-(
Thanks for posting that, Bill. I didn't want to add a ppa to get it, so I searched for it and found something else: a gnome extension called Lock Keys which does the same thing. It works, and also gives you the option of showing when the num lock is on. (I turned that one off.) Lock Keys also gives you the option of an on-screen display when you first turn on the caps lock. You can't miss it when that comes on.
Thanks for the info, Mike.
I did another Google search and found out that for Mint 19, from the Menu, just type in "accessibility", without the quotes, into the search bar and it will bring up a menu for activating a Caps key indicator.
I deleted the PPA for a keylock indicator, from the Repository, in Synaptic and rebooted my notebook, but the keylock indicator, is still functioning. So I can't try out the Mint Accessibility, caps lock indicator, until I get rid of the PPA keylock indicator.
I might be wrong, but deleting the PPA only removes that repository from your repository list that is scanned for updates. You should still be able to remove the app itself through either Synaptic or the "sudo apt remove ..." command.
Thanks Mike. Yes, you are right. I just had to look up what PPA program was named, "indicator-keylock"