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Mon Jul 4 06:21:14 2005 UTC (9 years, 2 months ago) by fox2mike
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#97827 - Info on FAT + utf-8. Thanks to Sebastian Roeder for reporting, Marcelo Goes for the patch.

1 <?xml version='1.0' encoding="UTF-8"?>
2 <!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/utf-8.xml,v 1.27 2005/07/02 11:55:16 swift Exp $ -->
3 <!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 <author title="Editor">
15 <mail link="fox2mike@gentoo.org">Shyam Mani</mail>
16 </author>
17
18 <abstract>
19 This guide shows you how to set up and use the UTF-8 Unicode character set with
20 your Gentoo Linux system, after explaining the benefits of Unicode and more
21 specifically UTF-8.
22 </abstract>
23
24 <!-- The content of this document is licensed under the CC-BY-SA license -->
25 <!-- See http://creativecommons.org/licenses/by-sa/2.5 -->
26 <license />
27
28 <version>2.8</version>
29 <date>2005-07-04</date>
30
31 <chapter>
32 <title>Character Encodings</title>
33 <section>
34 <title>What is a Character Encoding?</title>
35 <body>
36
37 <p>
38 Computers do not understand text themselves. Instead, every character is
39 represented by a number. Traditionally, each set of numbers used to represent
40 alphabets and characters (known as a coding system, encoding or character set)
41 was limited in size due to limitations in computer hardware.
42 </p>
43
44 </body>
45 </section>
46 <section>
47 <title>The History of Character Encodings</title>
48 <body>
49
50 <p>
51 The most common (or at least the most widely accepted) character set is
52 <b>ASCII</b> (American Standard Code for Information Interchange). It is widely
53 held that ASCII is the most successful software standard ever. Modern ASCII
54 was standardised in 1986 (ANSI X3.4, RFC 20, ISO/IEC 646:1991, ECMA-6) by the
55 American National Standards Institute.
56 </p>
57
58 <p>
59 ASCII is strictly seven-bit, meaning that it uses bit patterns representable
60 with seven binary digits, which provides a range of 0 to 127 in decimal. These
61 include 32 non-visible control characters, most between 0 and 31, with the
62 final control character, DEL or delete at 127. Characters 32 to 126 are
63 visible characters: a space, punctuation marks, Latin letters and numbers.
64 </p>
65
66 <p>
67 The eighth bit in ASCII was originally used as a parity bit for error checking.
68 If this is not desired, it is left as 0. This means that, with ASCII, each
69 character is represented by a single byte.
70 </p>
71
72 <p>
73 Although ASCII was enough for communication in modern English, in other
74 European languages that include accented characters, things were not so easy.
75 The ISO 8859 standards were developed to meet these needs. They were backwards
76 compatible with ASCII, but instead of leaving the eighth bit blank, they used
77 it to allow another 127 characters in each encoding. ISO 8859's limitations
78 soon came to light, and there are currently 15 variants of the ISO 8859
79 standard (8859-1 through to 8859-15). Outside of the ASCII-compatible byte
80 range of these character sets, there is often conflict between the letters
81 represented by each byte. To complicate interoperability between character
82 encodings further, Windows-1252 is used in some versions of Microsoft Windows
83 instead for Western European languages. This is a superset of ISO 8859-1,
84 however it is different in several ways. These sets do all retain ASCII
85 compatibility, however.
86 </p>
87
88 <p>
89 The necessary development of completely different single-byte encodings for
90 non-Latin alphabets, such as EUC (Extended Unix Coding) which is used for
91 Japanese and Korean (and to a lesser extent Chinese) created more confusion,
92 while other operating systems still used different character sets for the same
93 languages, for example, Shift-JIS and ISO-2022-JP. Users wishing to view
94 cyrillic glyphs had to choose between KOI8-R for Russian and Bulgarian or
95 KOI8-U for Ukrainian, as well as all the other cyrillic encodings such as the
96 unsuccessful ISO 8859-5, and the common Windows-1251 set. All of these
97 character sets broke most compatibility with ASCII (although KOI8 encodings
98 place cyrillic characters in Latin order, so in case the eighth bit is
99 stripped, text is still decipherable on an ASCII terminal through case-reversed
100 transliteration.)
101 </p>
102
103 <p>
104 This has led to confusion, and also to an almost total inability for
105 multilingual communication, especially across different alphabets. Enter
106 Unicode.
107 </p>
108
109 </body>
110 </section>
111 <section>
112 <title>What is Unicode?</title>
113 <body>
114
115 <p>
116 Unicode throws away the traditional single-byte limit of character sets. It
117 uses 17 "planes" of 65,536 code points to describe a maximum of 1,114,112
118 characters. As the first plane, aka. "Basic Multilingual Plane" or BMP,
119 contains almost everything you will ever use, many have made the wrong
120 assumption that Unicode was a 16-bit character set.
121 </p>
122
123 <p>
124 Unicode has been mapped in many different ways, but the two most common are
125 <b>UTF</b> (Unicode Transformation Format) and <b>UCS</b> (Universal Character
126 Set). A number after UTF indicates the number of bits in one unit, while the
127 number after UCS indicates the number of bytes. UTF-8 has become the most
128 widespread means for the interchange of Unicode text as a result of its
129 eight-bit clean nature, and it is the subject of this document.
130 </p>
131
132 </body>
133 </section>
134 <section>
135 <title>UTF-8</title>
136 <body>
137
138 <p>
139 UTF-8 is a variable-length character encoding, which in this instance means
140 that it uses 1 to 4 bytes per symbol. So, the first UTF-8 byte is used for
141 encoding ASCII, giving the character set full backwards compatibility with
142 ASCII. UTF-8 means that ASCII and Latin characters are interchangeable with
143 little increase in the size of the data, because only the first bit is used.
144 Users of Eastern alphabets such as Japanese, who have been assigned a higher
145 byte range are unhappy, as this results in as much as a 50% redundancy in their
146 data.
147 </p>
148
149 </body>
150 </section>
151 <section>
152 <title>What UTF-8 Can Do for You</title>
153 <body>
154
155 <p>
156 UTF-8 allows you to work in a standards-compliant and internationally accepted
157 multilingual environment, with a comparatively low data redundancy. UTF-8 is
158 the preferred way for transmitting non-ASCII characters over the Internet,
159 through Email, IRC or almost any other medium. Despite this, many people regard
160 UTF-8 in online communication as abusive. It is always best to be aware of the
161 attitude towards UTF-8 in a specific channel, mailing list or Usenet group
162 before using <e>non-ASCII</e> UTF-8.
163 </p>
164
165 </body>
166 </section>
167 </chapter>
168
169 <chapter>
170 <title>Setting up UTF-8 with Gentoo Linux</title>
171 <section>
172 <title>Finding or Creating UTF-8 Locales</title>
173 <body>
174
175 <p>
176 Now that you understand the principles behind Unicode, you're ready to start
177 using UTF-8 with your system.
178 </p>
179
180 <p>
181 The preliminary requirement for UTF-8 is to have a version of glibc installed
182 that has national language support. The recommend means to do this is the
183 <path>/etc/locales.build</path> file in combination with the <c>userlocales</c>
184 USE flag. It is beyond the scope of this document to explain the usage of this
185 file though, luckily, the usage of this file is well documented in the comments
186 within it. It is also explained in the <uri
187 link="/doc/en/guide-localization.xml#doc_chap3_sect3"> Gentoo Localisation
188 Guide</uri>.
189 </p>
190
191 <p>
192 Next, we'll need to decide whether a UTF-8 locale is already available for our
193 language, or whether we need to create one.
194 </p>
195
196 <pre caption="Checking for an existing UTF-8 locale">
197 <comment>(Replace "en_GB" with your desired locale setting)</comment>
198 # <i>locale -a | grep 'en_GB'</i>
199 en_GB
200 en_GB.UTF-8
201 </pre>
202
203 <p>
204 From the output of this command line, we need to take the result with a suffix
205 similar to <c>.UTF-8</c>. If there is no result with a suffix similar to
206 <c>.UTF-8</c>, we need to create a UTF-8 compatible locale.
207 </p>
208
209 <note>
210 Only execute the following code listing if you do not have a UTF-8 locale
211 available for your language.
212 </note>
213
214 <pre caption="Creating a UTF-8 locale">
215 <comment>(Replace "en_GB" with your desired locale setting)</comment>
216 # <i>localedef -i en_GB -f UTF-8 en_GB.UTF-8</i>
217 </pre>
218
219 <p>
220 Another way to include a UTF-8 locale is to add it to the
221 <path>/etc/locales.build</path> file and rebuild <c>glibc</c> with the
222 <c>userlocales</c> USE flag set.
223 </p>
224
225 <pre caption="Line in /etc/locales.build">
226 en_GB.UTF-8/UTF-8
227 </pre>
228
229 </body>
230 </section>
231 <section>
232 <title>Setting the Locale</title>
233 <body>
234
235 <p>
236 There is one environment variable that needs to be set in order to use
237 our new UTF-8 locales: <c>LC_ALL</c> (this variable overrides the <c>LANG</c>
238 setting as well). There are also many different ways to set it; some people
239 prefer to only have a UTF-8 environment for a specific user, in which case
240 they set them in their <path>~/.profile</path> (if you use <c>/bin/sh</c>),
241 <path>~/.bash_profile</path> or <path>~/.bashrc</path> (if you use
242 <c>/bin/bash</c>).
243 </p>
244
245 <p>
246 Others prefer to set the locale globally. One specific circumstance where
247 the author particularly recommends doing this is when
248 <path>/etc/init.d/xdm</path> is in use, because
249 this init script starts the display manager and desktop before any of the
250 aforementioned shell startup files are sourced, and so before any of the
251 variables are in the environment.
252 </p>
253
254 <p>
255 Setting the locale globally should be done using
256 <path>/etc/env.d/02locale</path>. The file should look something like the
257 following:
258 </p>
259
260 <pre caption="Demonstration /etc/env.d/02locale">
261 <comment>(As always, change "en_GB.UTF-8" to your locale)</comment>
262 LC_ALL="en_GB.UTF-8"
263 </pre>
264
265 <p>
266 Next, the environment must be updated with the change.
267 </p>
268
269 <pre caption="Updating the environment">
270 # <i>env-update</i>
271 >>> Regenerating /etc/ld.so.cache...
272 * Caching service dependencies ...
273 # <i>source /etc/profile</i>
274 </pre>
275
276 <p>
277 Now, run <c>locale</c> with no arguments to see if we have the correct
278 variables in our environment:
279 </p>
280
281 <pre caption="Checking if our new locale is in the environment">
282 # <i>locale</i>
283 LANG=
284 LC_CTYPE="en_GB.UTF-8"
285 LC_NUMERIC="en_GB.UTF-8"
286 LC_TIME="en_GB.UTF-8"
287 LC_COLLATE="en_GB.UTF-8"
288 LC_MONETARY="en_GB.UTF-8"
289 LC_MESSAGES="en_GB.UTF-8"
290 LC_PAPER="en_GB.UTF-8"
291 LC_NAME="en_GB.UTF-8"
292 LC_ADDRESS="en_GB.UTF-8"
293 LC_TELEPHONE="en_GB.UTF-8"
294 LC_MEASUREMENT="en_GB.UTF-8"
295 LC_IDENTIFICATION="en_GB.UTF-8"
296 LC_ALL=en_GB.UTF-8
297 </pre>
298
299 <p>
300 That's everything. You are now using UTF-8 locales, and the next hurdle is the
301 configuration of the applications you use from day to day.
302 </p>
303
304 </body>
305 </section>
306 </chapter>
307
308 <chapter>
309 <title>Application Support</title>
310 <section>
311 <body>
312
313 <p>
314 When Unicode first started gaining momentum in the software world, multibyte
315 character sets were not well suited to languages like C, in which many of the
316 day-to-day programs people use are written. Even today, some programs are not
317 able to handle UTF-8 properly. Fortunately, most are!
318 </p>
319
320 </body>
321 </section>
322 <section>
323 <title>Filenames, NTFS, and FAT</title>
324 <body>
325
326 <p>
327 There are several NLS options in the Linux kernel configuration menu, but it is
328 important to not become confused! For the most part, the only thing you need to
329 do is to build UTF-8 NLS support into your kernel, and change the default NLS
330 option to utf8.
331 </p>
332
333 <pre caption="Kernel configuration steps for UTF-8 NLS">
334 File Systems --&gt;
335 Native Language Support --&gt;
336 (utf8) Default NLS Option
337 &lt;*&gt; NLS UTF8
338 <comment>(Also &lt;*&gt; other character sets that are in use in
339 your FAT filesystems or Joilet CD-ROMs.)</comment>
340 </pre>
341
342 <p>
343 If you plan on mounting NTFS partitions, you may need to specify an <c>nls=</c>
344 option with mount. If you plan on mounting FAT partitions, you many need to
345 specify a <c>codepage=</c> option with mount. Optionally, you can also set a
346 default codepage for FAT in the kernel configuration. Note that the
347 <c>codepage</c> option with mount will override the kernel settings.
348 </p>
349
350 <pre caption="FAT settings in kernel configuration">
351 File Systems --&gt;
352 DOS/FAT/NT Filesystems --&gt;
353 (437) Default codepage for fat
354 </pre>
355
356 <p>
357 You should avoid setting <c>Default iocharset for fat</c> to UTF-8, as it is
358 not recommended. Instead, you may want to pass the option utf8=true when
359 mounting your FAT partitions. For further information, see <c>man mount</c> and
360 the kernel documentation at
361 <path>/usr/src/linux/Documentation/filesystems/vfat.txt</path>.
362 </p>
363
364 <p>
365 For changing the encoding of filenames, <c>app-text/convmv</c> can be used.
366 </p>
367
368 <pre caption="Example usage of convmv">
369 # <i>emerge --ask app-text/convmv</i>
370 # <i>convmv -f current-encoding -t utf-8 filename</i>
371 </pre>
372
373 <p>
374 For changing the <e>contents</e> of files, use the <c>iconv</c> utility,
375 bundled with <c>glibc</c>:
376 </p>
377
378 <pre caption="Example usage of iconv">
379 <comment>(substitute iso-8859-1 with the charset you are converting from)</comment>
380 <comment>(Check the output is sane)</comment>
381 # <i>iconv -f iso-8859-1 -t utf-8 filename</i>
382 <comment>(Convert a file, you must create another file)</comment>
383 # <i>iconv -f iso-8859-1 -t utf-8 filename > newfile</i>
384 </pre>
385
386 <p>
387 <c>app-text/recode</c> can also be used for this purpose.
388 </p>
389
390 </body>
391 </section>
392 <section>
393 <title>The System Console</title>
394 <body>
395
396 <impo>
397 You need >=sys-apps/baselayout-1.11.9 for Unicode on the console.
398 </impo>
399
400 <p>
401 To enable UTF-8 on the console, you should edit <path>/etc/rc.conf</path> and
402 set <c>UNICODE="yes"</c>, and also read the comments in that file -- it is
403 important to have a font that has a good range of characters if you plan on
404 making the most of Unicode.
405 </p>
406
407 <p>
408 The <c>KEYMAP</c> variable, set in <path>/etc/conf.d/keymaps</path>, should
409 have a Unicode keymap specified.
410 </p>
411
412 <pre caption="Example /etc/conf.d/keymaps snippet">
413 <comment>(Change "uk" to your local layout)</comment>
414 KEYMAP="uk"
415 </pre>
416
417 </body>
418 </section>
419 <section>
420 <title>Ncurses and Slang</title>
421 <body>
422
423 <note>
424 Ignore any mention of Slang in this section if you do not have it installed or
425 do not use it.
426 </note>
427
428 <p>
429 It is wise to add <c>unicode</c> to your global USE flags in
430 <path>/etc/make.conf</path>, and then to remerge <c>sys-libs/ncurses</c> and
431 <c>sys-libs/slang</c> if appropriate:
432 </p>
433
434 <pre caption="Emerging ncurses and slang">
435 <comment>(We avoid putting these libraries in our world file with --oneshot)</comment>
436 # <i>emerge --oneshot sys-libs/ncurses sys-libs/slang</i>
437 </pre>
438
439 <p>
440 We also need to rebuild packages that link to these, now the USE changes have
441 been applied. The tool we use (<c>revdep-rebuild</c>) is part of the
442 <c>gentoolkit</c> package.
443 </p>
444
445 <pre caption="Rebuilding of programs that link to ncurses or slang">
446 # <i>revdep-rebuild --soname libncurses.so.5</i>
447 # <i>revdep-rebuild --soname libslang.so.1</i>
448 </pre>
449
450 </body>
451 </section>
452 <section>
453 <title>KDE, GNOME and Xfce</title>
454 <body>
455
456 <p>
457 All of the major desktop environments have full Unicode support, and will
458 require no further setup than what has already been covered in this guide. This
459 is because the underlying graphical toolkits (Qt or GTK+2) are UTF-8 aware.
460 Subsequently, all applications running on top of these toolkits should be
461 UTF-8-aware out of the box.
462 </p>
463
464 <p>
465 The exceptions to this rule come in Xlib and GTK+1. GTK+1 requires a
466 iso-10646-1 FontSpec in the ~/.gtkrc, for example
467 <c>-misc-fixed-*-*-*-*-*-*-*-*-*-*-iso10646-1</c>. Also, applications using
468 Xlib or Xaw will need to be given a similar FontSpec, otherwise they will not
469 work.
470 </p>
471
472 <note>
473 If you have a version of the gnome1 control center around, use that instead.
474 Pick any iso10646-1 font from there.
475 </note>
476
477 <pre caption="Example ~/.gtkrc (for GTK+1) that defines a Unicode compatible font">
478 style "user-font"
479 {
480 fontset="-misc-fixed-*-*-*-*-*-*-*-*-*-*-iso10646-1"
481 }
482 widget_class "*" style "user-font"
483 </pre>
484
485 <p>
486 If an application has support for both a Qt and GTK+2 GUI, the GTK+2 GUI will
487 generally give better results with Unicode.
488 </p>
489
490 </body>
491 </section>
492 <section>
493 <title>X11 and Fonts</title>
494 <body>
495
496 <impo>
497 <c>x11-base/xorg-x11</c> has far better support for Unicode than XFree86
498 and is <e>highly</e> recommended.
499 </impo>
500
501 <p>
502 TrueType fonts have support for Unicode, and most of the fonts that ship with
503 Xorg have impressive character support, although, obviously, not every single
504 glyph available in Unicode has been created for that font. To build fonts
505 (including the Bitstream Vera set) with support for East Asian letters with X,
506 make sure you have the <c>cjk</c> USE flag set. Many other applications utilise
507 this flag, so it may be worthwhile to add it as a permanent USE flag.
508 </p>
509
510 <p>
511 Also, several font packages in Portage are Unicode aware.
512 </p>
513
514 <pre caption="Optional: Install some more Unicode-aware fonts">
515 # <i>emerge terminus-font intlfonts freefonts cronyx-fonts corefonts</i>
516 </pre>
517
518 </body>
519 </section>
520 <section>
521 <title>Window Managers and Terminal Emulators</title>
522 <body>
523
524 <p>
525 Window managers not built on GTK or Qt generally have very good Unicode
526 support, as they often use the Xft library for handling fonts. If your window
527 manager does not use Xft for fonts, you can still use the FontSpec mentioned in
528 the previous section as a Unicode font.
529 </p>
530
531 <p>
532 Terminal emulators that use Xft and support Unicode are harder to come by.
533 Aside from Konsole and gnome-terminal, the best options in Portage are
534 <c>x11-terms/rxvt-unicode</c>, <c>xfce-extra/terminal</c>,
535 <c>gnustep-apps/terminal</c>, <c>x11-terms/mlterm</c>, <c>x11-terms/mrxvt</c> or
536 plain <c>x11-terms/xterm</c> when built with the <c>unicode</c> USE flag and
537 invoked as <c>uxterm</c>. <c>app-misc/screen</c> supports UTF-8 too, when
538 invoked as <c>screen -u</c> or the following is put into the
539 <path>~/.screenrc</path>:
540 </p>
541
542 <pre caption="~/.screenrc for UTF-8">
543 defutf8 on
544 </pre>
545
546 </body>
547 </section>
548 <section>
549 <title>Vim, Emacs, Xemacs and Nano</title>
550 <body>
551
552 <p>
553 Vim provides full UTF-8 support, and also has builtin detection of UTF-8 files.
554 For further information in Vim, use <c>:help mbyte.txt</c>.
555 </p>
556
557 <p>
558 Emacs 22.x and higher has full UTF-8 support as well. Xemacs 22.x does not
559 support combining characters yet.
560 </p>
561
562 <p>
563 Lower versions of Emacs and/or Xemacs might require you to install
564 <c>app-emacs/mule-ucs</c> and/or <c>app-xemacs/mule-ucs</c>
565 and add the following code to your <path>~/.emacs</path> to have support for CJK
566 languages in UTF-8:
567 </p>
568
569 <pre caption="Emacs CJK UTF-8 support">
570 (require 'un-define)
571 (require 'jisx0213)
572 (set-language-environment "Japanese")
573 (set-default-coding-systems 'utf-8)
574 (set-terminal-coding-system 'utf-8)
575 </pre>
576
577 <p>
578 Nano currently does not provide support for UTF-8, although it has been planned
579 for a long time. With luck, this will change in future. At the time of writing,
580 UTF-8 support is in Nano's CVS, and should be included in the next release.
581 </p>
582
583 </body>
584 </section>
585 <section>
586 <title>Shells</title>
587 <body>
588
589 <p>
590 Currently, <c>bash</c> provides full Unicode support through the GNU readline
591 library. Z Shell users are in a somewhat worse position -- no parts of the
592 shell have Unicode support, although there is a concerted effort to add
593 multibyte character set support underway at the moment.
594 </p>
595
596 <p>
597 The C shell, <c>tcsh</c> and <c>ksh</c> do not provide UTF-8 support at all.
598 </p>
599
600 </body>
601 </section>
602 <section>
603 <title>Irssi</title>
604 <body>
605
606 <p>
607 Since 0.8.10, Irssi has complete UTF-8 support, although it does require a user
608 to set an option.
609 </p>
610
611 <pre caption="Enabling UTF-8 in Irssi">
612 /set term_charset UTF-8
613 </pre>
614
615 <p>
616 For channels where non-ASCII characters are often exchanged in non-UTF-8
617 charsets, the <c>/recode</c> command may be used to convert the characters.
618 Type <c>/help recode</c> for more information.
619 </p>
620
621 </body>
622 </section>
623 <section>
624 <title>Mutt</title>
625 <body>
626
627 <p>
628 The Mutt mail user agent has very good Unicode support. To use UTF-8 with Mutt,
629 put the following in your <path>~/.muttrc</path>:
630 </p>
631
632 <pre caption="~/.muttrc for UTF-8">
633 set send_charset="utf8" <comment>(outgoing character set)</comment>
634 set charset="utf8" <comment>(display character set)</comment>
635 </pre>
636
637 <note>
638 You may still see '?' in mail you read with Mutt. This is a result of people
639 using a mail client which does not indicate the used charset. You can't do much
640 about this than to ask them to configure their client correctly.
641 </note>
642
643 <p>
644 Further information is available from the <uri
645 link="http://wiki.mutt.org/index.cgi?MuttFaq/Charset">Mutt Wiki</uri>.
646 </p>
647
648 </body>
649 </section>
650 <section>
651 <title>Less</title>
652 <body>
653
654 <p>
655 We all use a lot of <c>more</c> or <c>less</c> along with the <c>|</c> to be
656 able to correctly see the output of a command, like for example
657 <c>dmesg | less</c>. While <c>more</c> only needs the shell to be UTF-8 aware,
658 <c>less</c> needs an environment variable set, <c>LESSCHARSET</c> to ensure
659 that unicode characters are rendered correctly. This can be set in
660 <path>/etc/profile</path> or <path>~/.bash_profile</path>. Fire up the editor
661 of your choice and the add the following line to one of the files mentioned
662 above.
663 </p>
664
665 <pre caption="Setting up the Environment variable for less">
666 LESSCHARSET=utf-8
667 </pre>
668
669 </body>
670 </section>
671 <section>
672 <title>Man</title>
673 <body>
674
675 <p>
676 Man pages are an integral part of any Linux machine. To ensure that any
677 unicode in your man pages render correctly, edit <path>/etc/man.conf</path>
678 and replace a line as shown below.
679 </p>
680
681 <pre caption="man.conf changes for Unicode support">
682 <comment>(This is the old line)</comment>
683 NROFF /usr/bin/nroff -Tascii -c -mandoc
684 <comment>(Replace the one above with this)</comment>
685 NROFF /usr/bin/nroff -mandoc -c
686 </pre>
687
688 </body>
689 </section>
690 <section>
691 <title>elinks and links</title>
692 <body>
693
694 <p>
695 These are commonly used text-based browsers, and we shall see how we can enable
696 UTF-8 support on them. On <c>elinks</c> and <c>links</c>, there are two ways to
697 go about this, one using the Setup option from within the browser or editing the
698 config file. To set the option through the browser, open a site with
699 <c>elinks</c> or <c>links</c> and then <c>Alt+S</c> to enter the Setup Menu then
700 select Terminal options, or press <c>T</c>. Scroll down and select the last
701 option <c>UTF-8 I/O</c> by pressing Enter. Then Save and exit the menu. On
702 <c>links</c> you may have to do a repeat <c>Alt+S</c> and then press <c>S</c> to
703 save. The config file option, is shown below.
704 </p>
705
706 <pre caption="Enabling UTF-8 for elinks/links">
707 <comment>(For elinks, edit /etc/elinks/elinks.conf or ~/.elinks/elinks.conf and
708 add the following line)</comment>
709 set terminal.linux.utf_8_io = 1
710
711 <comment>(For links, edit ~/.links/links.cfg and add the following
712 line)</comment>
713 terminal "xterm" 0 1 0 us-ascii utf-8
714 </pre>
715
716 </body>
717 </section>
718 <section>
719 <title>Testing it all out</title>
720 <body>
721
722 <p>
723 There are numerous UTF-8 test websites around. <c>net-www/w3m</c>,
724 <c>net-www/links</c>, <c>net-www/elinks</c>, <c>net-www/lynx</c> and all
725 Mozilla based browsers (including Firefox) support UTF-8. Konqueror and Opera
726 have full UTF-8 support too.
727 </p>
728
729 <p>
730 When using one of the text-only web browsers, make absolutely sure you are
731 using a Unicode-aware terminal.
732 </p>
733
734 <p>
735 If you see certain characters displayed as boxes with letters or numbers
736 inside, this means that your font does not have a character for the symbol or
737 glyph that the UTF-8 wants. Instead, it displays a box with the hex code of the
738 UTF-8 symbol.
739 </p>
740
741 <ul>
742 <li>
743 <uri link="http://www.w3.org/2001/06/utf-8-test/UTF-8-demo.html">A W3C
744 UTF-8 Test Page</uri>
745 </li>
746 <li>
747 <uri link="http://titus.uni-frankfurt.de/indexe.htm?/unicode/unitest.htm">
748 A UTF-8 test page provided by the University of Frankfurt</uri>
749 </li>
750 </ul>
751
752 </body>
753 </section>
754 <section>
755 <title>Input Methods</title>
756 <body>
757
758 <p>
759 <e>Dead keys</e> may be used to input characters in X that are not included on
760 your keyboard. These work by pressing your right Alt key (or in some countries,
761 AltGr) and an optional key from the non-alphabetical section of the keyboard to
762 the left of the return key at once, releasing them, and then pressing a letter.
763 The dead key should modify it. Input can be further modified by using the Shift
764 key at the same time as pressing the AltGr and modifier.
765 </p>
766
767 <p>
768 To enable dead keys in X, you need a layout that supports it. Most European
769 layouts already have dead keys with the default variant. However, this is not
770 true of North American layouts. Although there is a degree of inconsistency
771 between layouts, the easiest solution seems to be to use a layout in the form
772 "en_US" rather than "us", for example. The layout is set in
773 <path>/etc/X11/xorg.conf</path> like so:
774 </p>
775
776 <pre caption="/etc/X11/xorg.conf snippet">
777 Section "InputDevice"
778 Identifier "Keyboard0"
779 Driver "kbd"
780 Option "XkbLayout" "en_US" <comment># Rather than just "us"</comment>
781 <comment>(Other Xkb options here)</comment>
782 EndSection
783 </pre>
784
785 <note>
786 The preceding change only needs to be applied if you are using a North American
787 layout, or another layout where dead keys do not seem to be working. European
788 users should have working dead keys as is.
789 </note>
790
791 <p>
792 This change will come into effect when your X server is restarted. To apply the
793 change now, use the <c>setxkbmap</c> tool, for example, <c>setxkbmap en_US</c>.
794 </p>
795
796 <p>
797 It is probably easiest to describe dead keys with examples. Although the
798 results are locale dependent, the concepts should remain the same regardless of
799 locale. The examples contain UTF-8, so to view them you need to either tell
800 your browser to view the page as UTF-8, or have a UTF-8 locale already
801 configured.
802 </p>
803
804 <p>
805 When I press AltGr and [ at once, release them, and then press a, 'ä' is
806 produced. When I press AltGr and [ at once, and then press e, 'ë' is produced.
807 When I press AltGr and ; at once, 'á' is produced, and when I press AltGr and ;
808 at once, release them, and then press e, 'é' is produced.
809 </p>
810
811 <p>
812 By pressing AltGr, Shift and [ at once, releasing them, and then pressing a, a
813 Scandinavian 'å' is produced. Similarly, when I press AltGr, Shift and [ at
814 once, release <e>only</e> the [, and then press it again, '˚' is produced.
815 Although it looks like one, this (U+02DA) is not the same as a degree symbol
816 (U+00B0). This works for other accents produced by dead keys — AltGr and [,
817 releasing only the [, then pressing it again makes '¨'.
818 </p>
819
820 <p>
821 AltGr can be used with alphabetical keys alone. For example, AltGr and m, a
822 Greek lower-case letter mu is produced: 'µ'. AltGr and s produce a
823 scharfes s or esszet: 'ß'. As many European users would expect (because
824 it is marked on their keyboard), AltGr and 4 produces a Euro sign, '€'.
825 </p>
826
827 </body>
828 </section>
829 <section>
830 <title>Resources</title>
831 <body>
832
833 <ul>
834 <li>
835 <uri link="http://www.wikipedia.com/wiki/Unicode">The Wikipedia entry for
836 Unicode</uri>
837 </li>
838 <li>
839 <uri link="http://www.wikipedia.com/wiki/UTF-8">The Wikipedia entry for
840 UTF-8</uri>
841 </li>
842 <li><uri link="http://www.unicode.org">Unicode.org</uri></li>
843 <li><uri link="http://www.utf-8.com">UTF-8.com</uri></li>
844 <li><uri link="http://www.ietf.org/rfc/rfc3629.txt">RFC 3629</uri></li>
845 <li><uri link="http://www.ietf.org/rfc/rfc2277.txt">RFC 2277</uri></li>
846 <li>
847 <uri
848 link="http://www.tbray.org/ongoing/When/200x/2003/04/26/UTF">Characters vs.
849 Bytes</uri>
850 </li>
851 </ul>
852
853 </body>
854 </section>
855 </chapter>
856 </guide>

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