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16:12 <@slarti> SwifT: could you do something for me very quickly? there's two
                tiny tiny errors in utf-8.xml. I just need you to
                s/LOCALE=/LANG=/ and also to take out the leading space from #
                <i>source /etc/profile</i> so that it isn't indented

1 neysx 1.1 <?xml version='1.0' encoding="UTF-8"?>
2 swift 1.13 <!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/utf-8.xml,v 1.12 2005/04/24 14:11:51 bennyc Exp $ -->
3 neysx 1.1 <!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
4    
5     <guide link="/doc/en/utf-8.xml">
6     <title>Using UTF-8 with Gentoo</title>
7    
8     <author title="Author">
9     <mail link="slarti@gentoo.org">Thomas Martin</mail>
10     </author>
11     <author title="Contributor">
12     <mail link="devil@gentoo.org.ua">Alexander Simonov</mail>
13     </author>
14    
15     <abstract>
16     This guide shows you how to set up and use the UTF-8 Unicode character set with
17     your Gentoo Linux system, after explaining the benefits of Unicode and more
18     specifically UTF-8.
19     </abstract>
20    
21     <license />
22    
23 swift 1.13 <version>1.9</version>
24     <date>2005-04-24</date>
25 neysx 1.1
26     <chapter>
27     <title>Character Encodings</title>
28     <section>
29     <title>What is a Character Encoding?</title>
30     <body>
31    
32     <p>
33     Computers do not understand text themselves. Instead, every character is
34     represented by a number. Traditionally, each set of numbers used to represent
35     alphabets and characters (known as a coding system, encoding or character set)
36     was limited in size due to limitations in computer hardware.
37     </p>
38    
39     </body>
40     </section>
41     <section>
42     <title>The History of Character Encodings</title>
43     <body>
44    
45     <p>
46     The most common (or at least the most widely accepted) character set is
47     <b>ASCII</b> (American Standard Code for Information Interchange). It is widely
48     held that ASCII is the most successful software standard ever. Modern ASCII
49     was standardised in 1986 (ANSI X3.4, RFC 20, ISO/IEC 646:1991, ECMA-6) by the
50     American National Standards Institute.
51     </p>
52    
53     <p>
54     ASCII is strictly seven-bit, meaning that it uses bit patterns representable
55     with seven binary digits, which provides a range of 0 to 127 in decimal. These
56     include 32 non-visible control characters, most between 0 and 31, with the
57     final control character, DEL or delete at 127. Characters 32 to 126 are
58     visible characters: a space, punctuation marks, Latin letters and numbers.
59     </p>
60    
61     <p>
62     The eighth bit in ASCII was originally used as a parity bit for error checking.
63     If this is not desired, it is left as 0. This means that, with ASCII, each
64     character is represented by a single byte.
65     </p>
66    
67     <p>
68     Although ASCII was enough for communication in modern English, in other
69     European languages that include accented characters, things were not so easy.
70     The ISO 8859 standards were developed to meet these needs. They were backwards
71     compatible with ASCII, but instead of leaving the eighth bit blank, they used
72     it to allow another 127 characters in each encoding. ISO 8859's limitations
73     soon came to light, and there are currently 15 variants of the ISO 8859
74     standard (8859-1 through to 8859-15). Outside of the ASCII-compatible byte
75     range of these character sets, there is often conflict between the letters
76     represented by each byte. To complicate interoperability between character
77     encodings further, Windows-1252 is used in some versions of Microsoft Windows
78     instead for Western European languages. This is a superset of ISO 8859-1,
79     however it is different in several ways. These sets do all retain ASCII
80     compatibility, however.
81     </p>
82    
83     <p>
84     The necessary development of completely different single-byte encodings for
85     non-Latin alphabets, such as EUC (Extended Unix Coding) which is used for
86     Japanese and Korean (and to a lesser extent Chinese) created more confusion,
87     while other operating systems still used different character sets for the same
88     languages, for example, Shift-JIS and ISO-2022-JP. Users wishing to view
89     cyrillic glyphs had to choose between KOI8-R for Russian and Bulgarian or
90     KOI8-U for Ukrainian, as well as all the other cyrillic encodings such as the
91     unsuccessful ISO 8859-5, and the common Windows-1251 set. All of these
92     character sets broke most compatibility with ASCII (although KOI8 encodings
93     place cyrillic characters in Latin order, so in case the eighth bit is
94     stripped, text is still decipherable on an ASCII terminal through case-reversed
95     transliteration.)
96     </p>
97    
98     <p>
99     This has led to confusion, and also to an almost total inability for
100     multilingual communication, especially across different alphabets. Enter
101     Unicode.
102     </p>
103    
104     </body>
105     </section>
106     <section>
107     <title>What is Unicode?</title>
108     <body>
109    
110     <p>
111 bennyc 1.11 Unicode throws away the traditional single-byte limit of character sets. It
112     uses 17 "planes" of 65,536 code points to describe a maximum of 1,114,112
113     characters. As the first plane, aka. "Basic Multilingual Plane" or BMP,
114     contains almost everything you will ever use, many have made the wrong
115     assumption that Unicode was a 16-bit character set.
116 neysx 1.1 </p>
117    
118     <p>
119     Unicode has been mapped in many different ways, but the two most common are
120     <b>UTF</b> (Unicode Transformation Format) and <b>UCS</b> (Universal Character
121     Set). A number after UTF indicates the number of bits in one unit, while the
122     number after UCS indicates the number of bytes. UTF-8 has become the most
123     widespread means for the interchange of Unicode text as a result of its
124     eight-bit clean nature, and it is the subject of this document.
125     </p>
126    
127     </body>
128     </section>
129     <section>
130     <title>UTF-8</title>
131     <body>
132    
133     <p>
134     UTF-8 is a variable-length character encoding, which in this instance means
135     that it uses 1 to 4 bytes per symbol. So, the first UTF-8 byte is used for
136     encoding ASCII, giving the character set full backwards compatibility with
137     ASCII. UTF-8 means that ASCII and Latin characters are interchangeable with
138     little increase in the size of the data, because only the first bit is used.
139     Users of Eastern alphabets such as Japanese, who have been assigned a higher
140     byte range are unhappy, as this results in as much as a 50% redundancy in their
141     data.
142     </p>
143    
144     </body>
145     </section>
146     <section>
147     <title>What UTF-8 Can Do for You</title>
148     <body>
149    
150     <p>
151     UTF-8 allows you to work in a standards-compliant and internationally accepted
152 bennyc 1.11 multilingual environment, with a comparatively low data redundancy. UTF-8 is
153 neysx 1.1 the preferred way for transmitting non-ASCII characters over the Internet,
154     through Email, IRC or almost any other medium. Despite this, many people regard
155     UTF-8 in online communication as abusive. It is always best to be aware of the
156     attitude towards UTF-8 in a specific channel, mailing list or Usenet group
157     before using <e>non-ASCII</e> UTF-8.
158     </p>
159    
160     </body>
161     </section>
162     </chapter>
163    
164     <chapter>
165     <title>Setting up UTF-8 with Gentoo Linux</title>
166     <section>
167     <title>Finding or Creating UTF-8 Locales</title>
168     <body>
169    
170     <p>
171     Now that you understand the principles behind Unicode, you're ready to start
172     using UTF-8 with your system.
173     </p>
174    
175     <p>
176     The preliminary requirement for UTF-8 is to have a version of glibc installed
177     that has national language support. The recommend means to do this is the
178     <path>/etc/locales.build</path> file in combination with the <c>userlocales</c>
179     USE flag. It is beyond the scope of this document to explain the usage of this
180     file though, luckily, the usage of this file is well documented in the comments
181     within it. It is also explained in the <uri
182     link="/doc/en/guide-localization.xml#doc_chap3_sect3"> Gentoo Localisation
183     Guide</uri>.
184     </p>
185    
186     <p>
187     Next, we'll need to decide whether a UTF-8 locale is already available for our
188     language, or whether we need to create one.
189     </p>
190    
191     <pre caption="Checking for an existing UTF-8 locale">
192     <comment>(Replace "en_GB" with your desired locale setting)</comment>
193     # <i>locale -a | grep 'en_GB'</i>
194     en_GB
195 bennyc 1.12 en_GB.UTF-8
196 neysx 1.1 </pre>
197    
198     <p>
199     From the output of this command line, we need to take the result with a suffix
200 bennyc 1.12 similar to <c>.UTF-8</c>. If there is no result with a suffix similar to
201     <c>.UTF-8</c>, we need to create a UTF-8 compatible locale.
202 neysx 1.1 </p>
203    
204     <note>
205     Only execute the following code listing if you do not have a UTF-8 locale
206     available for your language.
207     </note>
208    
209     <pre caption="Creating a UTF-8 locale">
210     <comment>(Replace "en_GB" with your desired locale setting)</comment>
211 bennyc 1.12 # <i>localedef -i en_GB -f UTF-8 en_GB.UTF-8</i>
212 neysx 1.1 </pre>
213    
214 bennyc 1.11 <p>
215     Another way to include a UTF-8 locale is to add it to the
216     <path>/etc/locales.build</path> file and rebuild <c>glibc</c> with the
217     <c>userlocales</c> USE flag set.
218     </p>
219    
220     <pre caption="Line in /etc/locales.build">
221     en_GB.UTF-8/UTF-8
222     </pre>
223    
224 neysx 1.1 </body>
225     </section>
226     <section>
227     <title>Setting the Locale</title>
228     <body>
229    
230     <p>
231 bennyc 1.12 There are two environment variables that need to be set in order to use
232     our new UTF-8 locales: <c>LANG</c> and <c>LC_ALL</c>. There are also
233     many different ways to set them; some people prefer to only have a UTF-8
234     environment for a specific user, in which case they set them in their
235     <path>~/.profile</path> or <path>~/.bashrc</path>. Others prefer to set the
236     locale globally. One specific circumstance where the author particularly
237     recommends doing this is when <path>/etc/init.d/xdm</path> is in use, because
238     this init script starts the display manager and desktop before any of the
239     aforementioned shell startup files are sourced, and so before any of the
240     variables are in the environment.
241 neysx 1.1 </p>
242    
243 bennyc 1.12 <p>
244     Setting the locale globally should be done using
245     <path>/etc/env.d/02local</path>. The file should look something like the
246     following:
247     </p>
248    
249     <pre caption="Demonstration /etc/env.d/02locale">
250     <comment>(As always, change "en_GB.UTF-8" to your locale)</comment>
251     LC_ALL="en_GB.UTF-8"
252 swift 1.13 LANG="en_GB.UTF-8"
253 bennyc 1.12 </pre>
254    
255     <p>
256     Next, the environment must be updated with the change.
257     </p>
258 bennyc 1.10
259 bennyc 1.12 <pre caption="Updating the environment">
260     # <i>env-update</i>
261     >>> Regenerating /etc/ld.so.cache...
262     * Caching service dependencies ...
263 swift 1.13 # <i>source /etc/profile</i>
264 bennyc 1.10 </pre>
265    
266 bennyc 1.12 <p>
267     Now, run <c>locale</c> with no arguments to see if we have the correct
268     variables in our environment:
269     </p>
270    
271     <pre caption="Checking if our new locale is in the environment">
272     # <i>locale</i>
273     LANG=en_GB.UTF-8
274     LC_CTYPE="en_GB.UTF-8"
275     LC_NUMERIC="en_GB.UTF-8"
276     LC_TIME="en_GB.UTF-8"
277     LC_COLLATE="en_GB.UTF-8"
278     LC_MONETARY="en_GB.UTF-8"
279     LC_MESSAGES="en_GB.UTF-8"
280     LC_PAPER="en_GB.UTF-8"
281     LC_NAME="en_GB.UTF-8"
282     LC_ADDRESS="en_GB.UTF-8"
283     LC_TELEPHONE="en_GB.UTF-8"
284     LC_MEASUREMENT="en_GB.UTF-8"
285     LC_IDENTIFICATION="en_GB.UTF-8"
286     LC_ALL=en_GB.UTF-8
287 neysx 1.1 </pre>
288    
289 bennyc 1.10 <p>
290 bennyc 1.12 That's everything. You are now using UTF-8 locales, and the next hurdle is the
291     configuration of the applications you use from day to day.
292 neysx 1.1 </p>
293    
294     </body>
295     </section>
296     </chapter>
297    
298     <chapter>
299     <title>Application Support</title>
300     <section>
301     <body>
302    
303     <p>
304     When Unicode first started gaining momentum in the software world, multibyte
305     character sets were not well suited to languages like C, in which many of the
306     day-to-day programs people use are written. Even today, some programs are not
307     able to handle UTF-8 properly. Fortunately, most are!
308     </p>
309    
310     </body>
311     </section>
312     <section>
313     <title>Filenames, NTFS, and FAT</title>
314     <body>
315    
316     <p>
317     There are several NLS options in the Linux kernel configuration menu, but it is
318     important to not become confused! For the most part, the only thing you need to
319     do is to build UTF-8 NLS support into your kernel, and change the default NLS
320     option to utf8.
321     </p>
322    
323     <pre caption="Kernel configuration steps for UTF-8 NLS">
324     File Systems --&gt;
325     Native Language Support --&gt;
326     (utf8) Default NLS Option
327     &lt;*&gt; NLS UTF8
328     <comment>(Also &lt;*&gt; other character sets that are in use in
329     your FAT filesystems or Joilet CD-ROMs.)</comment>
330     </pre>
331    
332     <p>
333     If you plan on mounting NTFS partitions, you may need to specify an <c>nls=</c>
334     option with mount. For more information, see <c>man mount</c>.
335     </p>
336    
337     <p>
338     For changing the encoding of filenames, <c>app-text/convmv</c> can be used.
339     </p>
340    
341     <pre caption="Example usage of convmv">
342     # <i>emerge --ask app-text/convmv</i>
343     # <i>convmv -f current-encoding -t utf-8 filename</i>
344     </pre>
345    
346     <p>
347     For changing the <e>contents</e> of files, use the <c>iconv</c> utility,
348     bundled with <c>glibc</c>:
349     </p>
350    
351     <pre caption="Example usage of iconv">
352     <comment>(substitute iso-8859-1 with the charset you are converting from)</comment>
353     <comment>(Check the output is sane)</comment>
354     # <i>iconv -f iso-8859-1 -t utf-8 filename</i>
355     <comment>(Convert a file, you must create another file)</comment>
356     # <i>iconv -f iso-8859-1 -t utf-8 filename > newfile</i>
357     </pre>
358    
359     <p>
360     <c>app-text/recode</c> can also be used for this purpose.
361     </p>
362    
363     </body>
364     </section>
365     <section>
366     <title>The System Console</title>
367     <body>
368    
369     <impo>
370     You need >=sys-apps/baselayout-1.11.9 for Unicode on the console.
371     </impo>
372    
373     <p>
374     To enable UTF-8 on the console, you should edit <path>/etc/rc.conf</path> and
375     set <c>UNICODE="yes"</c>, and also read the comments in that file -- it is
376     important to have a font that has a good range of characters if you plan on
377     making the most of Unicode.
378     </p>
379    
380     <p>
381     The <c>KEYMAP</c> variable, set in <path>/etc/conf.d/keymaps</path>, should
382     have a Unicode keymap specified. To do this, simply prepend the keymap already
383     specified there with -u.
384     </p>
385    
386     <pre caption="Example /etc/conf.d/keymaps snippet">
387     <comment>(Change "uk" to your local layout)</comment>
388 bennyc 1.11 KEYMAP="-u uk"
389 neysx 1.1 </pre>
390    
391     </body>
392     </section>
393     <section>
394     <title>Ncurses and Slang</title>
395     <body>
396    
397     <note>
398     Ignore any mention of Slang in this section if you do not have it installed or
399     do not use it.
400     </note>
401    
402     <p>
403     It is wise to add <c>unicode</c> to your global USE flags in
404     <path>/etc/make.conf</path>, and then to remerge <c>sys-libs/ncurses</c> and
405     also <c>sys-libs/slang</c> if appropriate:
406     </p>
407    
408     <pre caption="Emerging ncurses and slang">
409     <comment>(We avoid putting these libraries in our world file with --oneshot)</comment>
410     # <i>emerge --oneshot --verbose --ask sys-libs/ncurses sys-libs/slang</i>
411     </pre>
412    
413     <p>
414     We also need to rebuild packages that link to these, now the USE changes have
415 bennyc 1.11 been applied. The tool we use (<c>revdep-rebuild</c>) is part of the
416     <c>gentoolkit</c> package.
417 neysx 1.1 </p>
418    
419     <pre caption="Rebuilding of programs that link to ncurses or slang">
420     # <i>revdep-rebuild --soname libncurses.so.5</i>
421     # <i>revdep-rebuild --soname libslang.so.1</i>
422     </pre>
423    
424     </body>
425     </section>
426     <section>
427     <title>KDE, GNOME and Xfce</title>
428     <body>
429    
430     <p>
431     All of the major desktop environments have full Unicode support, and will
432     require no further setup than what has already been covered in this guide. This
433     is because the underlying graphical toolkits (Qt or GTK+2) are UTF-8 aware.
434     Subsequently, all applications running on top of these toolkits should be
435     UTF-8-aware out of the box.
436     </p>
437    
438     <p>
439     The exceptions to this rule come in Xlib and GTK+1. GTK+1 requires a
440     iso-10646-1 FontSpec in the ~/.gtkrc, for example
441     <c>-misc-fixed-*-*-*-*-*-*-*-*-*-*-iso10646-1</c>. Also, applications using
442     Xlib or Xaw will need to be given a similar FontSpec, otherwise they will not
443     work.
444     </p>
445    
446     <note>
447     If you have a version of the gnome1 control center around, use that instead.
448     Pick any iso10646-1 font from there.
449     </note>
450    
451     <pre caption="Example ~/.gtkrc (for GTK+1) that defines a Unicode compatible font">
452     style "user-font"
453     {
454     fontset="-misc-fixed-*-*-*-*-*-*-*-*-*-*-iso10646-1"
455     }
456     widget_class "*" style "user-font"
457     </pre>
458    
459     <p>
460     If an application has support for both a Qt and GTK+2 GUI, the GTK+2 GUI will
461     generally give better results with Unicode.
462     </p>
463    
464     </body>
465     </section>
466     <section>
467     <title>X11 and Fonts</title>
468     <body>
469    
470 bennyc 1.11 <impo>
471     <c>x11-base/xorg-x11</c> has far better support for Unicode than XFree86
472     and is <e>highly</e> recommended.
473     </impo>
474    
475 neysx 1.1 <p>
476     TrueType fonts have support for Unicode, and most of the fonts that ship with
477     Xorg have impressive character support, although, obviously, not every single
478     glyph available in Unicode has been created for that font. To build fonts
479     (including the Bitstream Vera set) with support for East Asian letters with X,
480     make sure you have the <c>cjk</c> USE flag set. Many other applications utilise
481     this flag, so it may be worthwhile to add it as a permanent USE flag.
482     </p>
483    
484     <p>
485     Also, several font packages in Portage are Unicode aware.
486     </p>
487    
488     <pre caption="Optional: Install some more Unicode-aware fonts">
489     # <i>emerge terminus-font intlfonts freefonts cronyx-fonts corefonts</i>
490     </pre>
491    
492     </body>
493     </section>
494     <section>
495     <title>Window Managers and Terminal Emulators</title>
496     <body>
497    
498     <p>
499 bennyc 1.11 Window managers not built on GTK or Qt generally have very good Unicode
500     support, as they often use the Xft library for handling fonts. If your window
501     manager does not use Xft for fonts, you can still use the FontSpec mentioned in
502     the previous section as a Unicode font.
503 neysx 1.1 </p>
504    
505     <p>
506     Terminal emulators that use Xft and support Unicode are harder to come by.
507     Aside from Konsole and gnome-terminal, the best options in Portage are
508     <c>x11-terms/rxvt-unicode</c>, <c>xfce-extra/terminal</c>,
509 cam 1.5 <c>gnustep-apps/terminal</c>, <c>x11-terms/mlterm</c>, <c>x11-terms/mrxvt</c> or
510 neysx 1.1 plain <c>x11-terms/xterm</c> when built with the <c>unicode</c> USE flag and
511     invoked as <c>uxterm</c>. <c>app-misc/screen</c> supports UTF-8 too, when
512 bennyc 1.11 invoked as <c>screen -u</c> or the following is put into the
513 neysx 1.1 <path>~/.screenrc</path>:
514     </p>
515    
516     <pre caption="~/.screenrc for UTF-8">
517     defutf8 on
518     </pre>
519    
520     </body>
521     </section>
522     <section>
523     <title>Vim, Emacs, Xemacs and Nano</title>
524     <body>
525    
526     <p>
527     Vim, Emacs and Xemacs provide full UTF-8 support, and also have builtin
528     detection of UTF-8 files. For further information in Vim, use <c>:help
529     mbyte.txt</c>.
530     </p>
531    
532     <p>
533     Nano currently does not provide support for UTF-8, although it has been planned
534     for a long time. With luck, this will change in future. At the time of writing,
535     UTF-8 support is in Nano's CVS, and should be included in the next release.
536     </p>
537    
538     </body>
539     </section>
540     <section>
541     <title>Shells</title>
542     <body>
543    
544     <p>
545     Currently, <c>bash</c> provides full Unicode support through the GNU readline
546     library. Z Shell users are in a somewhat worse position -- no parts of the
547     shell have Unicode support, although there is a concerted effort to add
548     multibyte character set support underway at the moment.
549     </p>
550    
551     <p>
552     The C shell, <c>tcsh</c> and <c>ksh</c> do not provide UTF-8 support at all.
553     </p>
554    
555     </body>
556     </section>
557     <section>
558     <title>Irssi</title>
559     <body>
560    
561     <p>
562 cam 1.5 Since 0.8.10, Irssi has complete UTF-8 support, although it does require a user
563     to set an option.
564 neysx 1.1 </p>
565    
566     <pre caption="Enabling UTF-8 in Irssi">
567     /set term_charset UTF-8
568     </pre>
569    
570     <p>
571     For channels where non-ASCII characters are often exchanged in non-UTF-8
572     charsets, the <c>/recode</c> command may be used to convert the characters.
573     Type <c>/help recode</c> for more information.
574     </p>
575    
576     </body>
577     </section>
578     <section>
579     <title>Mutt</title>
580     <body>
581    
582     <p>
583     The Mutt mail user agent has very good Unicode support. To use UTF-8 with Mutt,
584     put the following in your <path>~/.muttrc</path>:
585     </p>
586    
587     <pre caption="~/.muttrc for UTF-8">
588     set send_charset="utf8" <comment>(outgoing character set)</comment>
589     set charset="utf8" <comment>(display character set)</comment>
590     </pre>
591    
592     <note>
593     You may still see '?' in mail you read with Mutt. This is a result of people
594 bennyc 1.11 using a mail client which does not indicate the used charset. You can't do much
595     about this than to ask them to configure their client correctly.
596 neysx 1.1 </note>
597    
598     <p>
599     Further information is available from the <uri
600     link="http://wiki.mutt.org/index.cgi?MuttFaq/Charset"> Mutt WikiWiki</uri>.
601     </p>
602    
603     </body>
604     </section>
605     <section>
606     <title>Testing it all out</title>
607     <body>
608    
609     <p>
610     There are numerous UTF-8 test websites around. <c>net-www/w3m</c>,
611     <c>net-www/links</c>, <c>net-www/elinks</c>, <c>net-www/lynx</c> and all
612 cam 1.3 Mozilla based browsers (including Firefox) support UTF-8. Konqueror and Opera
613     have full UTF-8 support too.
614 neysx 1.1 </p>
615    
616     <p>
617     When using one of the text-only web browsers, make absolutely sure you are
618     using a Unicode-aware terminal.
619     </p>
620    
621     <p>
622     If you see certain characters displayed as boxes with letters or numbers
623     inside, this means that your font does not have a character for the symbol or
624     glyph that the UTF-8 wants. Instead, it displays a box with the hex code of the
625     UTF-8 symbol.
626     </p>
627    
628     <ul>
629     <li>
630     <uri link="http://www.w3.org/2001/06/utf-8-test/UTF-8-demo.html">A W3C
631     UTF-8 Test Page</uri>
632     </li>
633     <li>
634     <uri link="http://titus.uni-frankfurt.de/indexe.htm?/unicode/unitest.htm">
635     A UTF-8 test page provided by the University of Frankfurt</uri>
636     </li>
637     </ul>
638    
639     </body>
640     </section>
641     <section>
642     <title>Input Methods</title>
643     <body>
644    
645     <p>
646     <e>Dead keys</e> may be used to input characters in X that are not included on
647     your keyboard. These work by pressing your right Alt key (or in some countries,
648     AltGr) and an optional key from the non-alphabetical section of the keyboard to
649     the left of the return key at once, releasing them, and then pressing a letter.
650     The dead key should modify it. Input can be further modified by using the Shift
651     key at the same time as pressing the AltGr and modifier.
652     </p>
653    
654     <p>
655     To enable dead keys in X, you need a layout that supports it. Most European
656     layouts already have dead keys with the default variant. However, this is not
657     true of North American layouts. Although there is a degree of inconsistency
658     between layouts, the easiest solution seems to be to use a layout in the form
659     "en_US" rather than "us", for example. The layout is set in
660     <path>/etc/X11/xorg.conf</path> like so:
661     </p>
662    
663     <pre caption="/etc/X11/xorg.conf snippet">
664     Section "InputDevice"
665     Identifier "Keyboard0"
666     Driver "kbd"
667     Option "XkbLayout" "en_US" <comment># Rather than just "us"</comment>
668     <comment>(Other Xkb options here)</comment>
669     EndSection
670     </pre>
671    
672     <note>
673     The preceding change only needs to be applied if you are using a North American
674     layout, or another layout where dead keys do not seem to be working. European
675     users should have working dead keys as is.
676     </note>
677    
678     <p>
679 bennyc 1.11 This change will come into effect when your X server is restarted. To apply the
680 neysx 1.1 change now, use the <c>setxkbmap</c> tool, for example, <c>setxkbmap en_US</c>.
681     </p>
682    
683     <p>
684     It is probably easiest to describe dead keys with examples. Although the
685 bennyc 1.11 results are locale dependent, the concepts should remain the same regardless of
686 neysx 1.1 locale. The examples contain UTF-8, so to view them you need to either tell
687     your browser to view the page as UTF-8, or have a UTF-8 locale already
688     configured.
689     </p>
690    
691     <p>
692     When I press AltGr and [ at once, release them, and then press a, 'ä' is
693 bennyc 1.11 produced. When I press AltGr and [ at once, and then press e, 'ë' is produced.
694     When I press AltGr and ; at once, 'á' is produced, and when I press AltGr and ;
695     at once, release them, and then press e, 'é' is produced.
696 neysx 1.1 </p>
697    
698     <p>
699     By pressing AltGr, Shift and [ at once, releasing them, and then pressing a, a
700     Scandinavian 'å' is produced. Similarly, when I press AltGr, Shift and [ at
701     once, release <e>only</e> the [, and then press it again, '˚' is produced.
702     Although it looks like one, this (U+02DA) is not the same as a degree symbol
703     (U+00B0). This works for other accents produced by dead keys — AltGr and [,
704     releasing only the [, then pressing it again makes '¨'.
705     </p>
706    
707     <p>
708     AltGr can be used with alphabetical keys alone. For example, AltGr and m, a
709 bennyc 1.12 Greek lower-case letter mu is produced: 'µ'. AltGr and s produce a
710     scharfes s or esszet: 'ß'. As many European users would expect (because
711     it is marked on their keyboard), AltGr and 4 produces a Euro sign, '€'.
712 neysx 1.1 </p>
713    
714     </body>
715     </section>
716     <section>
717     <title>Resources</title>
718     <body>
719    
720     <ul>
721     <li>
722     <uri link="http://www.wikipedia.com/wiki/Unicode">The Wikipedia entry for
723     Unicode</uri>
724     </li>
725     <li>
726     <uri link="http://www.wikipedia.com/wiki/UTF-8">The Wikipedia entry for
727     UTF-8</uri>
728     </li>
729     <li><uri link="http://www.unicode.org">Unicode.org</uri></li>
730     <li><uri link="http://www.utf-8.com">UTF-8.com</uri></li>
731     <li><uri link="http://www.ietf.org/rfc/rfc3629.txt">RFC 3629</uri></li>
732     <li><uri link="http://www.ietf.org/rfc/rfc2277.txt">RFC 2277</uri></li>
733 bennyc 1.11 <li>
734     <uri
735     link="http://www.tbray.org/ongoing/When/200x/2003/04/26/UTF">Characters vs.
736     Bytes</uri>
737     </li>
738 neysx 1.1 </ul>
739    
740     </body>
741     </section>
742     </chapter>
743     </guide>

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