There are two parts here: a Colemak advertisement and shortcuts for entering various symbols easily (things like {, ≤, ∈, ç). Skip down a bit if you're only interested in the latter!

What keyboard layout do you use? Standard Qwerty, Dvorak, neo, Colemak, or something else?

I see only two reasons for abandoning Qwerty:

• Ease of typing. I haven't used neo, but both Colemak and Dvorak, after fingers become used to the new workloads, are significantly more comfortable to type on than Qwerty ever was. (This will probably lead to lower error rates and higher speeds when proficient, by the way.)

• Ease of entering symbols. Want to use signs like ÷, £, ä, → and ≠? Most of these have been available in some keyboard layouts for a long time, and others not too hard to enter anyway (e.g. compose+-+> yields → on linux), but they could be easier, especially characters like ä, ö, ü (or à, é, è, depending on language).

  My original reason, though, for customising keyboard layouts, is because, programming, I want to write things like while( list[i] != 0 ){ sum += list[i]; ++i; } a lot. Not having to grope for +, { and ! from difficult-to-reach positions is much nicer.

Whichever your reason for switching, you should bear another factor in mind: practicality. Consider:

• Shortcuts. Ctrl+C and Ctrl+Z are very common shortcuts — probably used more than 'z' and 'c' are entered themselves. Although you could change the bindings in most applications to use the same physical keys, this isn't so convenient and doesn't always work expectedly; for this reason I don't recommend Dvorak or neo.
• Can you use your layout on most machines? Unlike Dvorak, neo and standard Colemak, my layout is only available for linux and only where you can convince the administrator to install the layout.

The above explains why I use Colemak, but not what these files are. After a while I found Colemak really nice for typing on, but found myself always reaching for various symbols in wierd positions on the number row while programming. I write quite a bit of code:

x := 2*3
vec := { 1, 2, 3 }
// oh, and real operators:
x ∉ vec
(x ÷ 3) ∈ vec

that type of thing.

Colemak was designed to make English text easier to write; the author didn't try to optimise the positions of symbols. In fact, other than moving the semicolon/colon key, all symbol keys were left untouched to make colemak easier to learn. With that in mind, it shouldn't be surprising to find that someone tries to optimise symbol keys (indeed if you read through the colemak forums, you will find several other such attempts).

So what was my approach? Of course, the best keys on the keyboard are already taken — we use them for typing letters, not numbers, operators and other symbols. I took my inspiration from the neo layout: use an extra shift key. It turns out that XKB (the linux keyboard layout system) has good support for 4 levels of input per key (unshifted, with shift, with alt, with alt+shift). It even supports 8 levels per key (I think this is mainly used in Cyrillic languages). So all I had to do was activate a second shift key, and add some symbols to the other keys. Oh, and design a keyboard layout.

Have a look here: cyborg16

• colemak — US keyboard, colemak layout and progsyms
• colemak_ch — US keyboard, colemak layout, Swiss-inspired accented keys and progsyms
• colemak_ukch — UK keyboard, colemak layout, near-Swiss accented keys, and progsyms
• dvorak_uk — UK keyboard, Dvorak layout and progsyms
• basic (default variant) — US keyboard, qwerty layout and progsyms
• basic_uk — UK keyboard, qwerty layout and progsyms

Other variants are quite easy to think of, but since near limitless combinations are possible defining other variants is left as an exercise to the reader (see the section below on customising the layout).

Quite a bit of thought and time has gone into creating this layout.

• I started the design on the basis that a symmetrical layout (each key on the left hand corresponding to a related/opposite key on the right hand) would make it easier to remember. If you look at the operators and the brackets in particular you should be able to spot this symmetry; unfortunately there was no obvious way to apply this to all keys and still fit all the symbols I wanted in, hence the bottom row is rather a jumble.
• The design tries to make nearly all symbols you might want to use available on the standard 3 rows of the keyboard. Numbers (other than the frequently used 0 and 1) are left on the top row since they're not so difficult to access from there.
• I have "evolved" the design over time: every so often deciding such and such would be better there and another key could be placed over there. Unlike carpalx it's not computer optimised — it's me optimised to be easy to remember and comfortable to type on (I saw no obvious way to formalise comfort and memorability, and wasn't really convinced that the methods used in the carpalx generator took everything necessary into account).

So is this layout well optimised in general or more importantly for your usage? The answer isn't obvious (but most likely the answer is no: a more optimal layout could be found). However concentrating solely on whether or not this is the best layout is somewhat missing the point: the question you are probably asking is is it worth me learning? Of course, I cannot answer that for you, but I can tell you I find this layout a massive improvement over standard qwerty or colemak, not just for programming but also for writing plain text.

Symbols can also be entered using sequences: compose + - + > maps to →, for example. Many of these are available by default on linux; I've added a few more combinations like compose + f + a producing ∀.

If you're wondering what compose is or how to enable it, see https://help.ubuntu.com/community/ComposeKey (or just add compose:menu to your XKB options).

To use my extensions, copy or link the file XCompose to $HOME/.XCompose and restart applications. (For GTK applications I think some additional hack is necessary.)

Installation consists of three steps:

1. install the layout file
2. make graphical configuration tools aware of the new layout and variants (optional)
3. set the layout and a third-level modifier key

The first step is very easy: copy the layout file into the XKB layouts directory. Assuming this has the same location on your system as debian (and probably Ubuntu):

sudo cp cyborg16 /usr/share/X11/xkb/symbols/

As soon as you've done this, you can go ahead and call setxkbmap (below). But if you want to set the layout from the Gnome/KDE settings panel, you need to perform an extra step to tell the GUI about the new layout.

To do this, open the rules/base.xml file in a text editor:

sudo cp /usr/share/X11/xkb/rules/base.xml \
    /usr/share/X11/xkb/rules/base.xml.bak
sudoedit /usr/share/X11/xkb/rules/base.xml

(if the above doesn't work, try setting your EDITOR or VISUAL environment variable first: export VISUAL=kwrite or whatever).

This file is quite big and has three sections:

Find the end of the layoutList section and insert the contents of the [cyborg16-base.xml-extension][] file there (just before </layoutList>. Make sure the XML is valid (each opening <tag> has a corresponding closing </tag>). Save the file and close the editor (necessary for sudoedit to update the original), then log out and log back in (or restart). [I'm not entirely sure logging out and back in is necessary. Maybe it's only necessary to (close and freshly) start the keyboard layout configuration.]

If you successfully ammended the base.xml file as documented above, you should be able to use the Gnome/KDE settings panels to change the keyboard layout.

Note that this method does have a (dis)advantage: settings are only applied after logging in. This means you have to remember which layout you're using when giving gdm/kdm your password — fun.

To set the layout from the command-line, use setxkbmap:

setxkbmap cyborg16
# or
setxkbmap cyborg16 colemak

If you want to use a different variant, you can specify that too. You can also specify the keyborad model and extra options. I use the following (note that the layout is provided twice with two variants: colemak_ch is the default, and basic (qwerty) is the alternative layout — the grp:sclk_toggle option allows me to change between these by pressing the scroll-lock button):

setxkbmap -layout cyborg16,cyborg16 -variant colemak_ch,basic -option \
    -option grp:sclk_toggle,grp_led:caps,compose:menu,caps:backspace \
    -model thinkpad60

Note that you might also need to set the second modifier key used to access the third and forth levels of the layout; I use the right alt key, which is sometimes labelled AltGr (short for alternate graphic). Depending on your physical keyboard this may not seem massively comfortable to press all the time, but I soon found I got used to this — it's simply using your thumb in a way you're not used to using it.

The keyboard layout used to be set in xorg.conf. Maybe it still can be set there (I haven't tried recently), but (in debian linux at least) the layout is normally set in /etc/default/keyboard. Run

sudoedit /etc/default/keyboard

and change the XKBLAYOUT and optionally other lines. My file includes the following:

XKBMODEL="thinkpad60"
XKBLAYOUT="cyborg16"
XKBVARIANT="colemak_ch"
XKBOPTIONS="grp:sclk_toggle,grp_led:caps,compose:menu,caps:backspace"

After this change, linux should use the new layout for all users on boot (but note that desktop environment settings may override the system layout once a user logs in).

It appears that keymaps are compiled by xkbcomp and compiled versions are stored in /var/lib/xkb . If there is already a compiled keymap, it appears that it will be loaded. To use the latest version, you can either use setxkbmap via xkbcomp:

setxkbmap ... -print | xkbcomp - $DISPLAY

(this is not a good solution as it appears the compiled maps still get used on hotloading) or you can delete the files in /var/lib/xkb to force the compiled maps to be regenerated (still investigating whether this is a good solution).

The included rules are intended for XKB. If you're using Windows or Mac OS X you'll have to find out how to customise keyboard layouts and write your own rules. Please do share if you do this; I'm sure it's possible though I don't know how (maybe looking at the colemak installer would help you get started).

If you want to modify the layout, go ahead and modify the cyborg16 file. To keep things tidy, I suggest you only put symbols in the "prog_intl" section and create a new section if you want a different base keyboard variant. You can find names for several symbols in the international-symbols.txt file, and may want to edit the XML chunk in cyborg16-base.xml-extension if you create a new variant.

Terminology and syntax: everything in the cyborg16 file defines XKB's cyborg16 layout. Each section in the file defines a new variant; the default variant is called "basic". The command include "us(dvorak)" means import the rules of the dvorak variant of the us layout.