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1 neysx 1.1 <?xml version='1.0' encoding="UTF-8"?>
2 swift 1.16 <!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/utf-8.xml,v 1.15 2005/05/29 16:00:59 swift 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 1.16 <version>2.1</version>
24     <date>2005-06-02</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 swift 1.16 There is one environment variables that needs to be set in order to use
232     our new UTF-8 locales: <c>LC_ALL</c> (this variable overrides the <c>LANG</c> setting as well). There are also
233     many different ways to set it; some people prefer to only have a UTF-8
234 bennyc 1.12 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 swift 1.15 <path>/etc/env.d/02locale</path>. The file should look something like the
246 bennyc 1.12 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     </pre>
253    
254     <p>
255     Next, the environment must be updated with the change.
256     </p>
257 bennyc 1.10
258 bennyc 1.12 <pre caption="Updating the environment">
259     # <i>env-update</i>
260     >>> Regenerating /etc/ld.so.cache...
261     * Caching service dependencies ...
262 swift 1.13 # <i>source /etc/profile</i>
263 bennyc 1.10 </pre>
264    
265 bennyc 1.12 <p>
266     Now, run <c>locale</c> with no arguments to see if we have the correct
267     variables in our environment:
268     </p>
269    
270     <pre caption="Checking if our new locale is in the environment">
271     # <i>locale</i>
272 swift 1.16 LANG=
273 bennyc 1.12 LC_CTYPE="en_GB.UTF-8"
274     LC_NUMERIC="en_GB.UTF-8"
275     LC_TIME="en_GB.UTF-8"
276     LC_COLLATE="en_GB.UTF-8"
277     LC_MONETARY="en_GB.UTF-8"
278     LC_MESSAGES="en_GB.UTF-8"
279     LC_PAPER="en_GB.UTF-8"
280     LC_NAME="en_GB.UTF-8"
281     LC_ADDRESS="en_GB.UTF-8"
282     LC_TELEPHONE="en_GB.UTF-8"
283     LC_MEASUREMENT="en_GB.UTF-8"
284     LC_IDENTIFICATION="en_GB.UTF-8"
285     LC_ALL=en_GB.UTF-8
286 neysx 1.1 </pre>
287    
288 bennyc 1.10 <p>
289 bennyc 1.12 That's everything. You are now using UTF-8 locales, and the next hurdle is the
290     configuration of the applications you use from day to day.
291 neysx 1.1 </p>
292    
293     </body>
294     </section>
295     </chapter>
296    
297     <chapter>
298     <title>Application Support</title>
299     <section>
300     <body>
301    
302     <p>
303     When Unicode first started gaining momentum in the software world, multibyte
304     character sets were not well suited to languages like C, in which many of the
305     day-to-day programs people use are written. Even today, some programs are not
306     able to handle UTF-8 properly. Fortunately, most are!
307     </p>
308    
309     </body>
310     </section>
311     <section>
312     <title>Filenames, NTFS, and FAT</title>
313     <body>
314    
315     <p>
316     There are several NLS options in the Linux kernel configuration menu, but it is
317     important to not become confused! For the most part, the only thing you need to
318     do is to build UTF-8 NLS support into your kernel, and change the default NLS
319     option to utf8.
320     </p>
321    
322     <pre caption="Kernel configuration steps for UTF-8 NLS">
323     File Systems --&gt;
324     Native Language Support --&gt;
325     (utf8) Default NLS Option
326     &lt;*&gt; NLS UTF8
327     <comment>(Also &lt;*&gt; other character sets that are in use in
328     your FAT filesystems or Joilet CD-ROMs.)</comment>
329     </pre>
330    
331     <p>
332     If you plan on mounting NTFS partitions, you may need to specify an <c>nls=</c>
333     option with mount. For more information, see <c>man mount</c>.
334     </p>
335    
336     <p>
337     For changing the encoding of filenames, <c>app-text/convmv</c> can be used.
338     </p>
339    
340     <pre caption="Example usage of convmv">
341     # <i>emerge --ask app-text/convmv</i>
342     # <i>convmv -f current-encoding -t utf-8 filename</i>
343     </pre>
344    
345     <p>
346     For changing the <e>contents</e> of files, use the <c>iconv</c> utility,
347     bundled with <c>glibc</c>:
348     </p>
349    
350     <pre caption="Example usage of iconv">
351     <comment>(substitute iso-8859-1 with the charset you are converting from)</comment>
352     <comment>(Check the output is sane)</comment>
353     # <i>iconv -f iso-8859-1 -t utf-8 filename</i>
354     <comment>(Convert a file, you must create another file)</comment>
355     # <i>iconv -f iso-8859-1 -t utf-8 filename > newfile</i>
356     </pre>
357    
358     <p>
359     <c>app-text/recode</c> can also be used for this purpose.
360     </p>
361    
362     </body>
363     </section>
364     <section>
365     <title>The System Console</title>
366     <body>
367    
368     <impo>
369     You need >=sys-apps/baselayout-1.11.9 for Unicode on the console.
370     </impo>
371    
372     <p>
373     To enable UTF-8 on the console, you should edit <path>/etc/rc.conf</path> and
374     set <c>UNICODE="yes"</c>, and also read the comments in that file -- it is
375     important to have a font that has a good range of characters if you plan on
376     making the most of Unicode.
377     </p>
378    
379     <p>
380     The <c>KEYMAP</c> variable, set in <path>/etc/conf.d/keymaps</path>, should
381     have a Unicode keymap specified. To do this, simply prepend the keymap already
382     specified there with -u.
383     </p>
384    
385     <pre caption="Example /etc/conf.d/keymaps snippet">
386     <comment>(Change "uk" to your local layout)</comment>
387 bennyc 1.11 KEYMAP="-u uk"
388 neysx 1.1 </pre>
389    
390     </body>
391     </section>
392     <section>
393     <title>Ncurses and Slang</title>
394     <body>
395    
396     <note>
397     Ignore any mention of Slang in this section if you do not have it installed or
398     do not use it.
399     </note>
400    
401     <p>
402     It is wise to add <c>unicode</c> to your global USE flags in
403     <path>/etc/make.conf</path>, and then to remerge <c>sys-libs/ncurses</c> and
404     also <c>sys-libs/slang</c> if appropriate:
405     </p>
406    
407     <pre caption="Emerging ncurses and slang">
408     <comment>(We avoid putting these libraries in our world file with --oneshot)</comment>
409     # <i>emerge --oneshot --verbose --ask sys-libs/ncurses sys-libs/slang</i>
410     </pre>
411    
412     <p>
413     We also need to rebuild packages that link to these, now the USE changes have
414 bennyc 1.11 been applied. The tool we use (<c>revdep-rebuild</c>) is part of the
415     <c>gentoolkit</c> package.
416 neysx 1.1 </p>
417    
418     <pre caption="Rebuilding of programs that link to ncurses or slang">
419     # <i>revdep-rebuild --soname libncurses.so.5</i>
420     # <i>revdep-rebuild --soname libslang.so.1</i>
421     </pre>
422    
423     </body>
424     </section>
425     <section>
426     <title>KDE, GNOME and Xfce</title>
427     <body>
428    
429     <p>
430     All of the major desktop environments have full Unicode support, and will
431     require no further setup than what has already been covered in this guide. This
432     is because the underlying graphical toolkits (Qt or GTK+2) are UTF-8 aware.
433     Subsequently, all applications running on top of these toolkits should be
434     UTF-8-aware out of the box.
435     </p>
436    
437     <p>
438     The exceptions to this rule come in Xlib and GTK+1. GTK+1 requires a
439     iso-10646-1 FontSpec in the ~/.gtkrc, for example
440     <c>-misc-fixed-*-*-*-*-*-*-*-*-*-*-iso10646-1</c>. Also, applications using
441     Xlib or Xaw will need to be given a similar FontSpec, otherwise they will not
442     work.
443     </p>
444    
445     <note>
446     If you have a version of the gnome1 control center around, use that instead.
447     Pick any iso10646-1 font from there.
448     </note>
449    
450     <pre caption="Example ~/.gtkrc (for GTK+1) that defines a Unicode compatible font">
451     style "user-font"
452     {
453     fontset="-misc-fixed-*-*-*-*-*-*-*-*-*-*-iso10646-1"
454     }
455     widget_class "*" style "user-font"
456     </pre>
457    
458     <p>
459     If an application has support for both a Qt and GTK+2 GUI, the GTK+2 GUI will
460     generally give better results with Unicode.
461     </p>
462    
463     </body>
464     </section>
465     <section>
466     <title>X11 and Fonts</title>
467     <body>
468    
469 bennyc 1.11 <impo>
470     <c>x11-base/xorg-x11</c> has far better support for Unicode than XFree86
471     and is <e>highly</e> recommended.
472     </impo>
473    
474 neysx 1.1 <p>
475     TrueType fonts have support for Unicode, and most of the fonts that ship with
476     Xorg have impressive character support, although, obviously, not every single
477     glyph available in Unicode has been created for that font. To build fonts
478     (including the Bitstream Vera set) with support for East Asian letters with X,
479     make sure you have the <c>cjk</c> USE flag set. Many other applications utilise
480     this flag, so it may be worthwhile to add it as a permanent USE flag.
481     </p>
482    
483     <p>
484     Also, several font packages in Portage are Unicode aware.
485     </p>
486    
487     <pre caption="Optional: Install some more Unicode-aware fonts">
488     # <i>emerge terminus-font intlfonts freefonts cronyx-fonts corefonts</i>
489     </pre>
490    
491     </body>
492     </section>
493     <section>
494     <title>Window Managers and Terminal Emulators</title>
495     <body>
496    
497     <p>
498 bennyc 1.11 Window managers not built on GTK or Qt generally have very good Unicode
499     support, as they often use the Xft library for handling fonts. If your window
500     manager does not use Xft for fonts, you can still use the FontSpec mentioned in
501     the previous section as a Unicode font.
502 neysx 1.1 </p>
503    
504     <p>
505     Terminal emulators that use Xft and support Unicode are harder to come by.
506     Aside from Konsole and gnome-terminal, the best options in Portage are
507     <c>x11-terms/rxvt-unicode</c>, <c>xfce-extra/terminal</c>,
508 cam 1.5 <c>gnustep-apps/terminal</c>, <c>x11-terms/mlterm</c>, <c>x11-terms/mrxvt</c> or
509 neysx 1.1 plain <c>x11-terms/xterm</c> when built with the <c>unicode</c> USE flag and
510     invoked as <c>uxterm</c>. <c>app-misc/screen</c> supports UTF-8 too, when
511 bennyc 1.11 invoked as <c>screen -u</c> or the following is put into the
512 neysx 1.1 <path>~/.screenrc</path>:
513     </p>
514    
515     <pre caption="~/.screenrc for UTF-8">
516     defutf8 on
517     </pre>
518    
519     </body>
520     </section>
521     <section>
522     <title>Vim, Emacs, Xemacs and Nano</title>
523     <body>
524    
525     <p>
526     Vim, Emacs and Xemacs provide full UTF-8 support, and also have builtin
527     detection of UTF-8 files. For further information in Vim, use <c>:help
528     mbyte.txt</c>.
529     </p>
530    
531     <p>
532     Nano currently does not provide support for UTF-8, although it has been planned
533     for a long time. With luck, this will change in future. At the time of writing,
534     UTF-8 support is in Nano's CVS, and should be included in the next release.
535     </p>
536    
537     </body>
538     </section>
539     <section>
540     <title>Shells</title>
541     <body>
542    
543     <p>
544     Currently, <c>bash</c> provides full Unicode support through the GNU readline
545     library. Z Shell users are in a somewhat worse position -- no parts of the
546     shell have Unicode support, although there is a concerted effort to add
547     multibyte character set support underway at the moment.
548     </p>
549    
550     <p>
551     The C shell, <c>tcsh</c> and <c>ksh</c> do not provide UTF-8 support at all.
552     </p>
553    
554     </body>
555     </section>
556     <section>
557     <title>Irssi</title>
558     <body>
559    
560     <p>
561 cam 1.5 Since 0.8.10, Irssi has complete UTF-8 support, although it does require a user
562     to set an option.
563 neysx 1.1 </p>
564    
565     <pre caption="Enabling UTF-8 in Irssi">
566     /set term_charset UTF-8
567     </pre>
568    
569     <p>
570     For channels where non-ASCII characters are often exchanged in non-UTF-8
571     charsets, the <c>/recode</c> command may be used to convert the characters.
572     Type <c>/help recode</c> for more information.
573     </p>
574    
575     </body>
576     </section>
577     <section>
578     <title>Mutt</title>
579     <body>
580    
581     <p>
582     The Mutt mail user agent has very good Unicode support. To use UTF-8 with Mutt,
583     put the following in your <path>~/.muttrc</path>:
584     </p>
585    
586     <pre caption="~/.muttrc for UTF-8">
587     set send_charset="utf8" <comment>(outgoing character set)</comment>
588     set charset="utf8" <comment>(display character set)</comment>
589     </pre>
590    
591     <note>
592     You may still see '?' in mail you read with Mutt. This is a result of people
593 bennyc 1.11 using a mail client which does not indicate the used charset. You can't do much
594     about this than to ask them to configure their client correctly.
595 neysx 1.1 </note>
596    
597     <p>
598     Further information is available from the <uri
599     link="http://wiki.mutt.org/index.cgi?MuttFaq/Charset"> Mutt WikiWiki</uri>.
600     </p>
601    
602     </body>
603     </section>
604     <section>
605 swift 1.14 <title>Less</title>
606     <body>
607    
608     <p>
609     We all use a lot of <c>more</c> or <c>less</c> along with the <c>|</c> to be
610     able to correctly see the output of a command, like for example
611     <c>dmesg | less</c>. While <c>more</c> only needs the shell to be UTF-8 aware,
612     <c>less</c> needs an environment variable set, <c>LESSCHARSET</c> to ensure
613     that unicode characters are rendered correctly. This can be set in
614     <path>/etc/profile</path> or <path>~/.bash_profile</path>. Fire up the editor
615     of your choice and the add the following line to one of the files mentioned
616     above.
617     </p>
618    
619     <pre caption="Setting up the Environment variable for less">
620     LESSCHARSET=utf-8
621     </pre>
622    
623     </body>
624     </section>
625     <section>
626     <title>Man</title>
627     <body>
628    
629     <p>
630     Man pages are an integral part of any Linux machine. To ensure that any
631     unicode in your man pages render correctly, edit <path>/etc/man.conf</path>
632     and replace a line as shown below.
633     </p>
634    
635     <pre caption="man.conf changes for Unicode support">
636     <comment>(This is the old line)</comment>
637     NROFF /usr/bin/nroff -Tascii -c -mandoc
638     <comment>(Replace the one above with this)</comment>
639     NROFF /usr/bin/nroff -mandoc -c
640     </pre>
641    
642     </body>
643     </section>
644     <section>
645 neysx 1.1 <title>Testing it all out</title>
646     <body>
647    
648     <p>
649     There are numerous UTF-8 test websites around. <c>net-www/w3m</c>,
650     <c>net-www/links</c>, <c>net-www/elinks</c>, <c>net-www/lynx</c> and all
651 cam 1.3 Mozilla based browsers (including Firefox) support UTF-8. Konqueror and Opera
652     have full UTF-8 support too.
653 neysx 1.1 </p>
654    
655     <p>
656     When using one of the text-only web browsers, make absolutely sure you are
657     using a Unicode-aware terminal.
658     </p>
659    
660     <p>
661     If you see certain characters displayed as boxes with letters or numbers
662     inside, this means that your font does not have a character for the symbol or
663     glyph that the UTF-8 wants. Instead, it displays a box with the hex code of the
664     UTF-8 symbol.
665     </p>
666    
667     <ul>
668     <li>
669     <uri link="http://www.w3.org/2001/06/utf-8-test/UTF-8-demo.html">A W3C
670     UTF-8 Test Page</uri>
671     </li>
672     <li>
673     <uri link="http://titus.uni-frankfurt.de/indexe.htm?/unicode/unitest.htm">
674     A UTF-8 test page provided by the University of Frankfurt</uri>
675     </li>
676     </ul>
677    
678     </body>
679     </section>
680     <section>
681     <title>Input Methods</title>
682     <body>
683    
684     <p>
685     <e>Dead keys</e> may be used to input characters in X that are not included on
686     your keyboard. These work by pressing your right Alt key (or in some countries,
687     AltGr) and an optional key from the non-alphabetical section of the keyboard to
688     the left of the return key at once, releasing them, and then pressing a letter.
689     The dead key should modify it. Input can be further modified by using the Shift
690     key at the same time as pressing the AltGr and modifier.
691     </p>
692    
693     <p>
694     To enable dead keys in X, you need a layout that supports it. Most European
695     layouts already have dead keys with the default variant. However, this is not
696     true of North American layouts. Although there is a degree of inconsistency
697     between layouts, the easiest solution seems to be to use a layout in the form
698     "en_US" rather than "us", for example. The layout is set in
699     <path>/etc/X11/xorg.conf</path> like so:
700     </p>
701    
702     <pre caption="/etc/X11/xorg.conf snippet">
703     Section "InputDevice"
704     Identifier "Keyboard0"
705     Driver "kbd"
706     Option "XkbLayout" "en_US" <comment># Rather than just "us"</comment>
707     <comment>(Other Xkb options here)</comment>
708     EndSection
709     </pre>
710    
711     <note>
712     The preceding change only needs to be applied if you are using a North American
713     layout, or another layout where dead keys do not seem to be working. European
714     users should have working dead keys as is.
715     </note>
716    
717     <p>
718 bennyc 1.11 This change will come into effect when your X server is restarted. To apply the
719 neysx 1.1 change now, use the <c>setxkbmap</c> tool, for example, <c>setxkbmap en_US</c>.
720     </p>
721    
722     <p>
723     It is probably easiest to describe dead keys with examples. Although the
724 bennyc 1.11 results are locale dependent, the concepts should remain the same regardless of
725 neysx 1.1 locale. The examples contain UTF-8, so to view them you need to either tell
726     your browser to view the page as UTF-8, or have a UTF-8 locale already
727     configured.
728     </p>
729    
730     <p>
731     When I press AltGr and [ at once, release them, and then press a, 'ä' is
732 bennyc 1.11 produced. When I press AltGr and [ at once, and then press e, 'ë' is produced.
733     When I press AltGr and ; at once, 'á' is produced, and when I press AltGr and ;
734     at once, release them, and then press e, 'é' is produced.
735 neysx 1.1 </p>
736    
737     <p>
738     By pressing AltGr, Shift and [ at once, releasing them, and then pressing a, a
739     Scandinavian 'å' is produced. Similarly, when I press AltGr, Shift and [ at
740     once, release <e>only</e> the [, and then press it again, '˚' is produced.
741     Although it looks like one, this (U+02DA) is not the same as a degree symbol
742     (U+00B0). This works for other accents produced by dead keys — AltGr and [,
743     releasing only the [, then pressing it again makes '¨'.
744     </p>
745    
746     <p>
747     AltGr can be used with alphabetical keys alone. For example, AltGr and m, a
748 bennyc 1.12 Greek lower-case letter mu is produced: 'µ'. AltGr and s produce a
749     scharfes s or esszet: 'ß'. As many European users would expect (because
750     it is marked on their keyboard), AltGr and 4 produces a Euro sign, '€'.
751 neysx 1.1 </p>
752    
753     </body>
754     </section>
755     <section>
756     <title>Resources</title>
757     <body>
758    
759     <ul>
760     <li>
761     <uri link="http://www.wikipedia.com/wiki/Unicode">The Wikipedia entry for
762     Unicode</uri>
763     </li>
764     <li>
765     <uri link="http://www.wikipedia.com/wiki/UTF-8">The Wikipedia entry for
766     UTF-8</uri>
767     </li>
768     <li><uri link="http://www.unicode.org">Unicode.org</uri></li>
769     <li><uri link="http://www.utf-8.com">UTF-8.com</uri></li>
770     <li><uri link="http://www.ietf.org/rfc/rfc3629.txt">RFC 3629</uri></li>
771     <li><uri link="http://www.ietf.org/rfc/rfc2277.txt">RFC 2277</uri></li>
772 bennyc 1.11 <li>
773     <uri
774     link="http://www.tbray.org/ongoing/When/200x/2003/04/26/UTF">Characters vs.
775     Bytes</uri>
776     </li>
777 neysx 1.1 </ul>
778    
779     </body>
780     </section>
781     </chapter>
782     </guide>

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