A typical keyboard only has about 100 keys on it.
Most keys double up on characters (also called "glyphs"), thanks to the **Shift** key, and in some regions there are even three glyphs available on some keys.
Regardless of your region, though, there are some glyphs that don't make it onto your keyboard, but Linux provides access to these through the *compose* key.
There's no compose key on your keyboard, at least not by default, but you can designate a key you're not otherwise using as your compose key.
I use the **Alt** key to the right of the spacebar on my desktop keyboard, and the **Menu** key on my laptop.
## Setting a Compose key in GNOME
On the GNOME desktop, install the **Tweaks** application from your software repository.
You can also install it from a terminal (use `apt` for Debian-based distributions, and `dnf` for Fedora and similar):
```bash
$ sudo dnf install gnome-tweaks
```
Launch **Tweaks** and click on the **Keyboard & Mouse** category in the left column.
Locate the **Compose key** setting and choose a key to designate.
Close **Tweaks**.
## Setting a Compose key in KDE Plasma Desktop
On the KDE Plasma Desktop, open **System Settings** and navigate to the **Input Devices** control panel.
In the **Input Devices** panel, click the **Advanced** tab.
Find the **Compose key** list item and choose a key to designate.
Click the **Apply** button in the bottom right corner of the window and then close **System Settings**.
## Using compose sequences
To enter a hidden character, you press the compose key and then release it.
You're now in *compose mode*.
While in compose mode, you can press and release one key, and then another to combine characters.
For instance:
1. Press the compose key, and then release it. You are now in compose mode.
2. Press an apostrophe (**'**) and then release it.
3. Press the letter **E** and then release it. This is a valid combination, so you are now out of compose mode.
You've just typed the letter **É**!
Some compose sequences are the combination of just two keys, while others require 3 keys, and at least one special glyph uses a sequence of 4 key presses.
## The secret glyphs
It's a small world, so there's a good chance you've got friends whose names use glyphs that aren't native to your keyboard.
You can now stop skipping over diacritics and type names using the appropriate modifiers.
Here's a sample list of compose sequences for common diacritics:
* **'** + <letter> = á é í ó ú ć ń ý j́́ ẃ ź
* **`** + <letter> = à è ì ò ù ǹ ỳ ẁ
* **~** + <letter> = ã ẽ ĩ õ ũ ñ ỹ
* **^** + <letter> = â ê î ô û ĉ ŷ ĵ ŵ ẑ
* **u** + <letter> = ă ĕ ĭ ŏ ŭ
* **c** + **c** = č
* **-** + <letter> = ā ē ī ō ū đ
* **,** + <letter> = ą ę į ǫ ų ç ḑ ţ
That's not a complete list, but it covers a lot of the common ones.
## Currency
International banking gets a little easier thanks to the compose key, too:
My favourite "secret" glyph in Linux is the traditional Vulcan salutation, "Live long and prosper."
* **L** + **L** + **A** + **P** = 🖖
There are a lot more glyphs available through the compose key, and you it's fun to discover new ones by pressing random compose sequences.
A more methodical method to discover glyphs is to refer to the `Compose` file, located in `/usr/share/X11/locale/en_US.UTF-8` (adjust the exact path depending on the locale your keyboard uses).
That file can admittedly be overwhelming, as it consists of over 6,000 lines of compose sequences, many of which are complex combinations of ASCII and Unicode.
For a quick and easy reference of common and foundational sequences, you can [download our compose key cheatsheet](LINK TO CHEATSHEET).
It provides you with sequences covering mathematics, typography, music, arrows, diacritics, currency, and more.
