I would like to type the diameter symbol ⌀ and some other special characters in Kubuntu. I tried in Kmail, Korganizer, LibreOffice Writer. The only place that a keystroke combination worked was in this text entry box in Firefox. I found a tutorial on the Compose Key here:


and I set my compose key to Scroll Lock. But for Unicode entry it turns out the Compose key is not used.

I found the Unicode code for the diameter symbol (2300) here:


I found the method of Unicode Composition here:


Press Shift+Ctrl+U, release U, enter the hexadecimal (0123456789abcdef) Unicode character code point, then release Shift+Ctrl. An underlined u followed by the number will be displayed as you type.

I use English and Thai keyboards.


I have found no way to use the unicode character index (2300) for ⌀ to create ⌀ in a Kmail or a LibreOffice Writer document. I have found that the compose key can do it and easily. The compose key codes have worked in every document or environment I've tried them, including here in my browser. The trick is to know which compose code to use. For my system, I found my compose codes here:


Here is a post on Where can I find the full list of Compose combinations for my locale?

There is actually a lot in this file. You can create all kinds of characters. There is a section on Korean characters, and Greek. Fractions are pretty intuitive but you need to use the keyboard not the keypad. Here are a couple example lines from the Compose file:

<Multi_key> <o> <o>                 : "°"   degree # DEGREE SIGN
<Multi_key> <C> <equal>             : "€"   EuroSign # EURO SIGN

As you can see there are descriptions of the characters so you can easily search the file to find what you need - it's a large file (6146 lines).

Also, listed in Discover (Kubuntu's Software Center) is an application called Character that will insert special characters.

So, I'm <Multi_key> <colon> <parenright>

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