[tlug] Tip of the Day: Printing Keymap Table with xmodmap

["Josh Glover" <jmglov@example.com>]

xmodmap -pke

View the pretty version of this tip in the TLUG wiki:
http://tlug.jp/wiki/Linux_Help:Tip_of_the_Day:Printing_Keymap_Table_with_xmodmap

This tip is helpful when you have a (mostly) working keyboard, and one
that isn't working so well. For example, I have a Dell Latitude D410
laptop with a Japanese keyboard. For some odd reason, when I tell
X.org to use a jp106 keyboard model, the backslash / underscore / ã
key that is located just to the left of my right shift key does not
work. Neither do the various Japanese input-specific special keys (åè
/ åè / æå, çåæ, åæ, and ãããã / ãããã / ãããå), the Windows keys, or the
volume raise, lower, and mute keys. Luckily, I also have a jp106
keyboard on my Gentoo desktop.

Here's how I got my keymap on the Dell laptop straightened out.

  1. On the desktop, run:

     xmodmap -pke

     You will get a bunch of output like this:

     keycode  47 = semicolon plus kana_RE
     keycode  48 = colon asterisk kana_KE
     keycode  49 = Zenkaku_Hankaku Kanji
     keycode  50 = Shift_L

  2. On the laptop, open at least two terminal emulators
  3. In one term, cd to your home directory and edit the file
.xmodmaprc (this file most likely will not exist, and thus be empty
when you edit it)
  4. In the other term, run:

     xev

     This will launch a little window that, when it has focus, will
spew information about X events to the terminal from which it was
launched
  5. Get used to xev by giving it the focus, waiting for a second
until there is no new output to the terminal window, then pressing a
key. You should see out like this appear:

     KeyPress event, serial 27, synthetic NO, window 0x1600001,
         root 0x3b, subw 0x0, time 2049376201, (158,128), root:(1269,943),
         state 0x0, keycode 208 (keysym 0xff27, Hiragana_Katakana),
same_screen YES,
         XLookupString gives 0 bytes:
         XmbLookupString gives 0 bytes:
         XFilterEvent returns: False

     KeyRelease event, serial 30, synthetic NO, window 0x1600001,
         root 0x3b, subw 0x0, time 2049376297, (158,128), root:(1269,943),
         state 0x0, keycode 208 (keysym 0xff27, Hiragana_Katakana),
same_screen YES,
         XLookupString gives 0 bytes:

     The main thing you want to note here is the keycode, which will
be the second bit of data in the third line of every log statement
output in response to a KeyPress event.
  6. Now, follow these steps for each key that is not working on the laptop:
        1. On the laptop (i.e. non-working keyboard), give the xev
window the focus, wait a few seconds and press the troublesome key.
e.g. I press the backslash / underscore / ã key
        2. Note the keycode. e.g. I see

           KeyPress event, serial 27, synthetic NO, window 0x1600001,
               root 0x3b, subw 0x0, time 2049376201, (158,128),
root:(1269,943),
               state 0x0, keycode 211 (keysym 0x0, NoSymbol), same_screen YES,
               ...

           I note keycode 211.
        3. On the desktop (i.e. working keyboard), find the line that
corresponds to the key you are trying to map. Note that it may not
have the same keycode. In my example, I find the line

           keycode 211 = backslash underscore kana_RO

        4. On the laptop, switch to the terminal where you are
editing .xmodmaprc and enter the line just as it appeared in the
output of xmodmap -pke on the desktop, but changing the keycode if
necessary. e.g. I enter

           keycode 211 = backslash underscore kana_RO

  7. After entering mapping expressions into .xmodmaprc on the laptop
for each of your troublesome keys, save .xmodmaprc and exit
  8. Close xev by hitting Ctrl-C in the terminal from which you launched it
  9. Now, make sure that the command

     xmodmap ${HOME}/.xmodmaprc

     runs on startup of your window manager. If you are using an
old-school .xinitrc, simply add the line

     xmodmap ${HOME}/.xmodmaprc

     to the file before the window manager is started. GNOME / KDE
user: update this section to give instructions for running xmodmap on
startup!

Cheers,
Josh