Add the [compose key][wikipedia] to your [[Xmodmap]] file with something like

    keycode 134 = Multi_key

The compose key has it's own unicode symbol: ⎄, which I'll use in the
following composition tables.

Accents
-------

* ⎄`a à
* ⎄'a á
* ⎄^a â
* ⎄ca ǎ
* ⎄ba ă
* ⎄oa å
* ⎄!a ạ
* ⎄.a ȧ
* ⎄"a ä
* ⎄~a ã
* ⎄_a ā
* ⎄;a ą
* ⎄,c ç

Weird letters
-------------

* ⎄AE Æ
* ⎄ae æ
* ⎄ss ß
* ⎄TH Þ
* ⎄th þ

Currency
--------

* ⎄=C €
* ⎄|c ¢
* ⎄-L £

Typography
----------

* ⎄<< «
* ⎄>> »
* ⎄"< “
* ⎄"> ”
* ⎄'< ‘
* ⎄'> ’
* ⎄.. …
* ⎄p! ¶
* ⎄os §
* ⎄?? ¿
* ⎄!! ¡
* ⎄--- — (em dash)
* ⎄--. – (em dash)

Math
----

* ⎄oo °
* ⎄^0 ⁰
* ⎄^1 ¹
* ⎄_1 ₁
* ⎄12 ½
* ⎄+- ±
* ⎄xx ×
* ⎄:- ÷
* ⎄/o ø
* ⎄mu µ

Business
--------

* ⎄oc ©
* ⎄or ®
* ⎄tm ™

Emoticons
---------

* ⎄:) ☺
* ⎄:( ☹

As you can imagine, the list goes on and on.  The compositing system
depends on your application (see the [Ubuntu wiki][ubuntu] for Gnome
notes), but if you're using the X Input Method (XIM), your compose
table depends on your locale:

    $ echo $LANG
    en_US.UTF-8
    $ grep $LANG\$ /usr/share/X11/locale/compose.dir
    en_US.UTF-8/Compose             en_US.UTF-8
    en_US.UTF-8/Compose:            en_US.UTF-8
    $ less /usr/share/X11/locale/en_US.UTF-8/Compose

If you want to customize your compose keys, just add your own rules to
an `~/.XCompose` file:

    $ cat ~/.XCompose
    include "%L"

    <Multi_key> <h> <o> <m> <e> : "http://tremily.us/"  # Home page

Read `Compose(5)` for more information.  You may need to log out and
log back in (or use the [[newgrp]] trick) for your new `~/.XCompose`
file to take effect.

[wikipedia]: http://en.wikipedia.org/wiki/Compose_key
[ubuntu]: https://help.ubuntu.com/community/ComposeKey

[[!tag tags/fun]]
[[!tag tags/linux]]