How can I add a custom compose key sequence?

For example, I would like Compose, |, > to type the symbol.

I have tried adding the following to ~/.XCompose:

# Import default rules from the system Compose file
include "%L"

# Custom definitions
<Multi_key> <bar> <greater> : "▸" U25B8 # Black right-pointing small triangle

but the new sequence is not usable anywhere except for xterm.

Installing ibus-table-compose and then enabling the Compose input method in IBus did not solve the problem; IBus imitated many compose key sequences, but not the one I had created.

  • How do you type the symbol now? You could probably map the command you use to type the symbol to specific keys in keyboard layout. To find the exact keysym of a particular key, you can use xev . But ofcourse, this is just my guess. Jun 7, 2011 at 15:52
  • 3
    @nitstorm I typed it by pressing AltGr+>, which is a customized mapping that I set by adding the keysym U25B8 to keycode 60 in ~/.xmodmaprc. I'm not asking how to type ▸; I'm asking how to create a compose key sequence for it.
    – ændrük
    Jun 7, 2011 at 16:05

3 Answers 3

  1. Create a file named .XCompose in your home directory (~/.XCompose), which contains:

    # import the default Compose file for your locale
    include "%L"
    <Multi_key> <bar> <greater>  : "▸"

    See man 5 Compose for more info about the format of this file.

  2. Add the following to ~/.profile:

    export GTK_IM_MODULE="xim"

    On Ubuntu 18.04 (maybe others), you may need to use the following instead:

    export GTK_IM_MODULE="gtk-im-context-simple"
  3. Log off and back on. Or restart X. Or reboot.

  • 3
    I noticed that with this solution, I cannot use Ctrl-Shift-u anymore to insert unicode characters by number; so I take it that this switches something general away from the Gnome stuff to the X stuff which is configured by that ~/.XCompose file. Is there also a way to modify the Gnome stuff instead? I'd like to keep that Ctrl-Shift-u feature.
    – Alfe
    Jan 28, 2013 at 15:31
  • 2
    @Alfe Using UIM as suggested on the bottom of Ubuntu Forums: .XCompose file not read in 11.04 GNOME works for me with the default settings in Debian jessie/sid (see im-config(8) for customization). That is, .XCompose settings are working both in GTK (GNOME) and Qt (KDE) applications, and .XCompose and Ctrl+Shift+U are both working in GTK applications (like Eclipse). May 10, 2013 at 16:22
  • Thank you! So did you just apt-get the uim package or did you have to configure something else?
    – Alfe
    May 10, 2013 at 19:59
  • 1
    I tried to get this running for some time now, but to no avail. It'd be very helpful to hear what exactly you did besides installing the uim package. At least this could help to be sure that your way doesn't work on Ubuntu 12.04.
    – Alfe
    May 10, 2013 at 22:32
  • 1
    Note that the default of GTK_IM_MODULE=ibus worked fine for me (using 18.04).
    – MPi
    Sep 5, 2018 at 15:33

Create a file ~/.XCompose (that is a file named .XCompose in your "home" folder) which contains the following:

include "%L"   # import the default Compose file for your locale
<Multi_key> <bar> <greater>     : "▸"

See man 5 Compose for more info about the format of this file.

  • 4
    Neat! Is there any way to have this file re-read without restarting X? Jun 8, 2011 at 7:10
  • 1
    This sounds promising, but my ~/.XCompose file doesn't seem to have any effect even after rebooting. Have you gotten this to work?
    – ændrük
    Jun 8, 2011 at 15:49
  • @Jeremy: I'm not sure, but maybe changing the keyboard layout to another layout and then back might work.
    – JanC
    Jun 9, 2011 at 12:52
  • 1
    @ændrük: I seem to remember that Gtk/GNOME stupidly messes with the compose key settings (you can test if the new Compose key combination works in e.g. xterm to confirm this is the case). I seem to remember the workaround had something to do with selecting an alternative input method that bypasses the problematic medling; maybe ask a new question about that, because it's not only useful for this but IIRC it also fixes locale-specific Compose maps, etc. ;)
    – JanC
    Jun 9, 2011 at 13:14
  • 1
    As of at least 18.04 LTS this answer should now work without needing to change input methods.
    – ændrük
    Nov 2, 2018 at 16:30

On Ubuntu 14.04 I did the following:

1) Installed uim using the Software Manager, other packages like uim-xim, uim-gtk2, uim-gtk3 and uim-qt are auto installed. See https://launchpad.net/ubuntu/+source/uim.

2) Defined environmental variables by adding the next lines to ~/.profile, this way the custom compose key sequences only apply to the current user:

# Restart the X-server after making alterations using:
# $ sudo restart lightdm
# It seems only GTK_IM_MODULE or QT_IM_MODULE needs to be defined.
export GTK_IM_MODULE="uim"
export QT_IM_MODULE="uim"

The ~/.XCompose-file from the OP should work after restarting 1) Ubuntu or 2) just the X-server by runnung the following command in a terminal:

$ sudo restart lightdm

NB: Restarting only seems necessary after altering the ~/.profile file, alterations to ~/.XCompose will take effect the next time an application (Terminal, Gedit, etc.) starts.

To check whether the environmental variables are set right, enter the following command in your terminal:

$ printenv | grep IM_MODULE

Many thanks to:

About custom compose key sequences:

About custom keyboard mapping:

Example .Xcompose files to mimic Window US International keyboards:

  • That’s what I did, but compose sequences inputs just nothing, nothing at all.
    – Hibou57
    Apr 27, 2020 at 19:24

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