For the longest time I have disabled my CapsLock key. I used to hit it from time to time and get annoyed by having to redo the bit I was typing, but this time not in all caps. For a little while I also used it in a keybinding, but found that using "VoidSymbol" (the key it will register as when disabled) is flakey. So this left me with a big button, right on the home row of my keyboard that does nothing at all, which is a waste.
In Dutch we use some special characters in writing, characters like é, è or ë. To be able to type these, I've always just relied on spell checking. It would underline a word like "Belgie", which is supposed to be "België" in Dutch (meaning Belgium) and I'd press F7 and it'd fix it for me. This works ok, but isn't great when you are in an application without spell checking. I've written a script in the past which would use Rofi and FZF to display a list of special characters, which I could then arrow through to select a character. On pressing enter it'd copy the character to my clipboard and I could paste it anywhere.
This was not great. Way too convoluted for just placing a special character in a text. This should be easier. Enter the Compose Key. Pressing the compose key begins a key press sequence that involves (usually two) additional key presses, which will then yield a character composed of the two. So for example pressing e, followed by ' (apostrophe/acute accent), will create é.
The compose key is not a physical key on the keyboard, but you can map any key to act as the compose key in Linux. So, I have a useless home row key and the need to be able to easily type special keys, which can be done by mapping a key to act as the compose key... I've added the following line to my autostart.sh file, which will remap CapsLock to the compose key:
setxkbmap -option compose:caps &
Now I am able to add special characters without any hassle! And it's not just the e key with markings, there are loads of possible combinations to create a special character. Some of my favorites:
And more can be found here.