···

       
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    XKB

     

       
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   </link>

     

       
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   keyboard layouts using the option

     

       
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-
       
   <option>

     

       
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-
       
    <link linkend="opt-services.xserver.extraLayouts">

     

       
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209
       
-
       
     services.xserver.extraLayouts

     

       
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-
       
    </link>

     

       
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-
       
   </option>.

     

       
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+
       
   <option><link linkend="opt-services.xserver.extraLayouts">

     

       
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+
       
     services.xserver.extraLayouts</link></option>.

     

       
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+
       
  </para>

     

       
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+
       
  <para>

     

       
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   As a first example, we are going to create a layout based on the basic US

     

       
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212
       
 
       
   layout, with an additional layer to type some greek symbols by pressing the

     

       
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213
       
 
       
   right-alt key.

     

       
215
       
214
       
 
       
  </para>

     

       
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  <para>

     

       
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217
       
-
       
   To do this we are going to create a <literal>us-greek</literal> file

     

       
218
       
218
       
-
       
   with a <literal>xkb_symbols</literal> section.

     

       
216
       
216
       
+
       
   Create a file called <literal>us-greek</literal> with the following

     

       
217
       
217
       
+
       
   content (under a directory called <literal>symbols</literal>; it's

     

       
218
       
218
       
+
       
   an XKB peculiarity that will help with testing):

     

       
219
       
219
       
 
       
  </para>

     

       
220
       
220
       
 
       
<programlisting>

     

       
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xkb_symbols &quot;us-greek&quot;

     
···

       
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231
       
 
       
};

     

       
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232
       
 
       
</programlisting>

     

       
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  <para>

     

       
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-
       
   To install the layout, the filepath, a description and the list of

     

       
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235
       
-
       
   languages must be given:

     

       
234
       
234
       
+
       
   A minimal layout specification must include the following:

     

       
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235
       
 
       
  </para>

     

       
237
       
236
       
 
       
<programlisting>

     

       
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237
       
 
       
<xref linkend="opt-services.xserver.extraLayouts"/>.us-greek = {

     

       
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238
       
 
       
  description = "US layout with alt-gr greek";

     

       
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  languages   = [ "eng" ];

     

       
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241
       
-
       
  symbolsFile = /path/to/us-greek;

     

       
240
       
240
       
+
       
  symbolsFile = /yourpath/symbols/us-greek;

     

       
242
       
241
       
 
       
}

     

       
243
       
242
       
 
       
</programlisting>

     

       
244
       
243
       
 
       
  <note>

     
···

       
248
       
247
       
 
       
  </para>

     

       
249
       
248
       
 
       
  </note>

     

       
250
       
249
       
 
       
  <para>

     

       
251
       
251
       
-
       
   The layout should now be installed and ready to use: try it by

     

       
252
       
252
       
-
       
   running <literal>setxkbmap us-greek</literal> and type

     

       
253
       
253
       
-
       
   <literal>&lt;alt&gt;+a</literal>. To change the default the usual

     

       
250
       
250
       
+
       
   Applying this customization requires rebuilding several packages,

     

       
251
       
251
       
+
       
   and a broken XKB file can lead to the X session crashing at login.

     

       
252
       
252
       
+
       
   Therefore, you're strongly advised to <emphasis role="strong">test

     

       
253
       
253
       
+
       
   your layout before applying it</emphasis>:

     

       
254
       
254
       
+
       
<screen>

     

       
255
       
255
       
+
       
<prompt>$ </prompt>nix-shell -p xorg.xkbcomp

     

       
256
       
256
       
+
       
<prompt>$ </prompt>setxkbmap -I/yourpath us-greek -print | xkbcomp -I/yourpath - $DISPLAY

     

       
257
       
257
       
+
       
</screen>

     

       
258
       
258
       
+
       
  </para>

     

       
259
       
259
       
+
       
  <para>

     

       
260
       
260
       
+
       
   You can inspect the predefined XKB files for examples:

     

       
261
       
261
       
+
       
<screen>

     

       
262
       
262
       
+
       
<prompt>$ </prompt>echo "$(nix-build --no-out-link '&lt;nixpkgs&gt;' -A xorg.xkeyboardconfig)/etc/X11/xkb/"

     

       
263
       
263
       
+
       
</screen>

     

       
264
       
264
       
+
       
  </para>

     

       
265
       
265
       
+
       
  <para>

     

       
266
       
266
       
+
       
   Once the configuration is applied, and you did a logout/login

     

       
267
       
267
       
+
       
   cycle, the layout should be ready to use. You can try it by e.g.

     

       
268
       
268
       
+
       
   running <literal>setxkbmap us-greek</literal> and then type

     

       
269
       
269
       
+
       
   <literal>&lt;alt&gt;+a</literal> (it may not get applied in your

     

       
270
       
270
       
+
       
   terminal straight away). To change the default, the usual

     

       
254
       
271
       
 
       
   <option>

     

       
255
       
272
       
 
       
    <link linkend="opt-services.xserver.layout">

     

       
256
       
273
       
 
       
     services.xserver.layout