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Revision: 1.51
Committed: Mon Nov 19 12:02:35 2007 UTC (16 years, 6 months ago) by root
Branch: MAIN
CVS Tags: rel-8_5a, rel-8_6
Changes since 1.50: +8 -8 lines
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# User Rev Content
1 root 1.42 RXVT-UNICODE/URXVT FREQUENTLY ASKED QUESTIONS
2     Meta, Features & Commandline Issues
3     My question isn't answered here, can I ask a human?
4     Before sending me mail, you could go to IRC: "irc.freenode.net", channel
5     "#rxvt-unicode" has some rxvt-unicode enthusiasts that might be
6     interested in learning about new and exciting problems (but not FAQs :).
7    
8     Does it support tabs, can I have a tabbed rxvt-unicode?
9     Beginning with version 7.3, there is a perl extension that implements a
10     simple tabbed terminal. It is installed by default, so any of these
11     should give you tabs:
12    
13     urxvt -pe tabbed
14    
15     URxvt.perl-ext-common: default,tabbed
16    
17     It will also work fine with tabbing functionality of many window
18     managers or similar tabbing programs, and its embedding-features allow
19     it to be embedded into other programs, as witnessed by doc/rxvt-tabbed
20     or the upcoming "Gtk2::URxvt" perl module, which features a tabbed urxvt
21     (murxvt) terminal as an example embedding application.
22    
23     How do I know which rxvt-unicode version I'm using?
24     The version number is displayed with the usage (-h). Also the escape
25     sequence "ESC [ 8 n" sets the window title to the version number. When
26     using the urxvtc client, the version displayed is that of the daemon.
27    
28     Rxvt-unicode uses gobs of memory, how can I reduce that?
29     Rxvt-unicode tries to obey the rule of not charging you for something
30     you don't use. One thing you should try is to configure out all settings
31     that you don't need, for example, Xft support is a resource hog by
32     design, when used. Compiling it out ensures that no Xft font will be
33     loaded accidentally when rxvt-unicode tries to find a font for your
34     characters.
35    
36     Also, many people (me included) like large windows and even larger
37     scrollback buffers: Without "--enable-unicode3", rxvt-unicode will use 6
38     bytes per screen cell. For a 160x?? window this amounts to almost a
39     kilobyte per line. A scrollback buffer of 10000 lines will then (if
40     full) use 10 Megabytes of memory. With "--enable-unicode3" it gets
41     worse, as rxvt-unicode then uses 8 bytes per screen cell.
42    
43     How can I start urxvtd in a race-free way?
44     Try "urxvtd -f -o", which tells urxvtd to open the display, create the
45     listening socket and then fork.
46    
47 root 1.45 How can I start urxvtd automatically when I run urxvtc?
48 root 1.42 If you want to start urxvtd automatically whenever you run urxvtc and
49     the daemon isn't running yet, use this script:
50    
51     #!/bin/sh
52     urxvtc "$@"
53     if [ $? -eq 2 ]; then
54     urxvtd -q -o -f
55     urxvtc "$@"
56     fi
57    
58     This tries to create a new terminal, and if fails with exit status 2,
59     meaning it couldn't connect to the daemon, it will start the daemon and
60     re-run the command. Subsequent invocations of the script will re-use the
61     existing daemon.
62    
63 root 1.43 How do I distinguish whether I'm running rxvt-unicode or a regular xterm? I need this to decide about setting colors etc.
64 root 1.42 The original rxvt and rxvt-unicode always export the variable
65     "COLORTERM", so you can check and see if that is set. Note that several
66     programs, JED, slrn, Midnight Commander automatically check this
67     variable to decide whether or not to use color.
68    
69     How do I set the correct, full IP address for the DISPLAY variable?
70     If you've compiled rxvt-unicode with DISPLAY_IS_IP and have enabled
71     insecure mode then it is possible to use the following shell script
72     snippets to correctly set the display. If your version of rxvt-unicode
73     wasn't also compiled with ESCZ_ANSWER (as assumed in these snippets)
74     then the COLORTERM variable can be used to distinguish rxvt-unicode from
75     a regular xterm.
76    
77     Courtesy of Chuck Blake <cblake@BBN.COM> with the following shell script
78     snippets:
79    
80     # Bourne/Korn/POSIX family of shells:
81     [ ${TERM:-foo} = foo ] && TERM=xterm # assume an xterm if we don't know
82     if [ ${TERM:-foo} = xterm ]; then
83     stty -icanon -echo min 0 time 15 # see if enhanced rxvt or not
84     echo -n '^[Z'
85     read term_id
86     stty icanon echo
87     if [ ""${term_id} = '^[[?1;2C' -a ${DISPLAY:-foo} = foo ]; then
88     echo -n '^[[7n' # query the rxvt we are in for the DISPLAY string
89     read DISPLAY # set it in our local shell
90     fi
91     fi
92    
93     How do I compile the manual pages on my own?
94     You need to have a recent version of perl installed as /usr/bin/perl,
95 root 1.49 one that comes with pod2man, pod2text and pod2xhtml (from Pod::Xhtml).
96 root 1.48 Then go to the doc subdirectory and enter "make alldoc".
97 root 1.42
98     Isn't rxvt-unicode supposed to be small? Don't all those features bloat?
99     I often get asked about this, and I think, no, they didn't cause extra
100     bloat. If you compare a minimal rxvt and a minimal urxvt, you can see
101     that the urxvt binary is larger (due to some encoding tables always
102     being compiled in), but it actually uses less memory (RSS) after
103     startup. Even with "--disable-everything", this comparison is a bit
104     unfair, as many features unique to urxvt (locale, encoding conversion,
105     iso14755 etc.) are already in use in this mode.
106    
107     text data bss drs rss filename
108     98398 1664 24 15695 1824 rxvt --disable-everything
109     188985 9048 66616 18222 1788 urxvt --disable-everything
110    
111     When you "--enable-everything" (which *is* unfair, as this involves xft
112     and full locale/XIM support which are quite bloaty inside libX11 and my
113 root 1.43 libc), the two diverge, but not unreasonably so.
114 root 1.42
115     text data bss drs rss filename
116     163431 2152 24 20123 2060 rxvt --enable-everything
117     1035683 49680 66648 29096 3680 urxvt --enable-everything
118    
119     The very large size of the text section is explained by the east-asian
120     encoding tables, which, if unused, take up disk space but nothing else
121     and can be compiled out unless you rely on X11 core fonts that use those
122     encodings. The BSS size comes from the 64k emergency buffer that my c++
123     compiler allocates (but of course doesn't use unless you are out of
124     memory). Also, using an xft font instead of a core font immediately adds
125     a few megabytes of RSS. Xft indeed is responsible for a lot of RSS even
126     when not used.
127    
128     Of course, due to every character using two or four bytes instead of
129     one, a large scrollback buffer will ultimately make rxvt-unicode use
130     more memory.
131    
132     Compared to e.g. Eterm (5112k), aterm (3132k) and xterm (4680k), this
133     still fares rather well. And compared to some monsters like
134     gnome-terminal (21152k + extra 4204k in separate processes) or konsole
135     (22200k + extra 43180k in daemons that stay around after exit, plus half
136     a minute of startup time, including the hundreds of warnings it spits
137     out), it fares extremely well *g*.
138    
139     Why C++, isn't that unportable/bloated/uncool?
140     Is this a question? :) It comes up very often. The simple answer is: I
141     had to write it, and C++ allowed me to write and maintain it in a
142     fraction of the time and effort (which is a scarce resource for me). Put
143     even shorter: It simply wouldn't exist without C++.
144    
145     My personal stance on this is that C++ is less portable than C, but in
146     the case of rxvt-unicode this hardly matters, as its portability limits
147     are defined by things like X11, pseudo terminals, locale support and
148     unix domain sockets, which are all less portable than C++ itself.
149    
150     Regarding the bloat, see the above question: It's easy to write programs
151     in C that use gobs of memory, an certainly possible to write programs in
152     C++ that don't. C++ also often comes with large libraries, but this is
153     not necessarily the case with GCC. Here is what rxvt links against on my
154     system with a minimal config:
155    
156     libX11.so.6 => /usr/X11R6/lib/libX11.so.6 (0x00002aaaaabc3000)
157     libc.so.6 => /lib/libc.so.6 (0x00002aaaaadde000)
158     libdl.so.2 => /lib/libdl.so.2 (0x00002aaaab01d000)
159     /lib64/ld-linux-x86-64.so.2 (0x00002aaaaaaab000)
160    
161     And here is rxvt-unicode:
162    
163     libX11.so.6 => /usr/X11R6/lib/libX11.so.6 (0x00002aaaaabc3000)
164     libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x00002aaaaada2000)
165 root 1.51 libc.so.6 => /lib/libc.so.6 (0x00002aaaaaeb0000)
166     libdl.so.2 => /lib/libdl.so.2 (0x00002aaaab0ee000)
167     /lib64/ld-linux-x86-64.so.2 (0x00002aaaaaaab000)
168 root 1.42
169     No large bloated libraries (of course, none were linked in statically),
170     except maybe libX11 :)
171    
172     Rendering, Font & Look and Feel Issues
173     I can't get transparency working, what am I doing wrong?
174 root 1.50 First of all, please address all transparency related issues to Sasha
175     Vasko at sasha@aftercode.net and do not bug the author about it. Also,
176     if you can't get it working consider it a rite of passage: ... and you
177     failed.
178 root 1.42
179     Here are four ways to get transparency. Do read the manpage and option
180     descriptions for the programs mentioned and rxvt-unicode. Really, do it!
181    
182 root 1.51 1. Use transparent mode:
183 root 1.42
184     Esetroot wallpaper.jpg
185 root 1.51 urxvt -tr -tint red -sh 40
186 root 1.42
187     That works. If you think it doesn't, you lack transparency and tinting
188     support, or you are unable to read.
189    
190     2. Use a simple pixmap and emulate pseudo-transparency. This enables you
191     to use effects other than tinting and shading: Just shade/tint/whatever
192     your picture with gimp or any other tool:
193    
194 root 1.50 convert wallpaper.jpg -blur 20x20 -modulate 30 background.jpg
195 root 1.51 urxvt -pixmap "background.jpg;:root"
196 root 1.42
197 root 1.51 That works. If you think it doesn't, you lack AfterImage support, or you
198     are unable to read.
199 root 1.42
200     3. Use an ARGB visual:
201    
202     urxvt -depth 32 -fg grey90 -bg rgba:0000/0000/4444/cccc
203    
204     This requires XFT support, and the support of your X-server. If that
205     doesn't work for you, blame Xorg and Keith Packard. ARGB visuals aren't
206     there yet, no matter what they claim. Rxvt-Unicode contains the
207 root 1.43 necessary bugfixes and workarounds for Xft and Xlib to make it work, but
208     that doesn't mean that your WM has the required kludges in place.
209 root 1.42
210     4. Use xcompmgr and let it do the job:
211    
212     xprop -frame -f _NET_WM_WINDOW_OPACITY 32c \
213     -set _NET_WM_WINDOW_OPACITY 0xc0000000
214    
215     Then click on a window you want to make transparent. Replace 0xc0000000
216     by other values to change the degree of opacity. If it doesn't work and
217     your server crashes, you got to keep the pieces.
218    
219     Why does rxvt-unicode sometimes leave pixel droppings?
220     Most fonts were not designed for terminal use, which means that
221     character size varies a lot. A font that is otherwise fine for terminal
222     use might contain some characters that are simply too wide. Rxvt-unicode
223     will avoid these characters. For characters that are just "a bit" too
224     wide a special "careful" rendering mode is used that redraws adjacent
225     characters.
226    
227     All of this requires that fonts do not lie about character sizes,
228     however: Xft fonts often draw glyphs larger than their acclaimed
229     bounding box, and rxvt-unicode has no way of detecting this (the correct
230     way is to ask for the character bounding box, which unfortunately is
231     wrong in these cases).
232    
233 root 1.43 It's not clear (to me at least), whether this is a bug in Xft, freetype,
234 root 1.42 or the respective font. If you encounter this problem you might try
235     using the "-lsp" option to give the font more height. If that doesn't
236     work, you might be forced to use a different font.
237    
238     All of this is not a problem when using X11 core fonts, as their
239     bounding box data is correct.
240    
241     How can I keep rxvt-unicode from using reverse video so much?
242     First of all, make sure you are running with the right terminal settings
243     ("TERM=rxvt-unicode"), which will get rid of most of these effects. Then
244     make sure you have specified colours for italic and bold, as otherwise
245     rxvt-unicode might use reverse video to simulate the effect:
246    
247     URxvt.colorBD: white
248     URxvt.colorIT: green
249    
250     Some programs assume totally weird colours (red instead of blue), how can I fix that?
251     For some unexplainable reason, some rare programs assume a very weird
252     colour palette when confronted with a terminal with more than the
253     standard 8 colours (rxvt-unicode supports 88). The right fix is, of
254     course, to fix these programs not to assume non-ISO colours without very
255     good reasons.
256    
257     In the meantime, you can either edit your "rxvt-unicode" terminfo
258     definition to only claim 8 colour support or use "TERM=rxvt", which will
259     fix colours but keep you from using other rxvt-unicode features.
260    
261     Can I switch the fonts at runtime?
262     Yes, using an escape sequence. Try something like this, which has the
263     same effect as using the "-fn" switch, and takes effect immediately:
264    
265     printf '\33]50;%s\007' "9x15bold,xft:Kochi Gothic"
266    
267     This is useful if you e.g. work primarily with japanese (and prefer a
268     japanese font), but you have to switch to chinese temporarily, where
269     japanese fonts would only be in your way.
270    
271     You can think of this as a kind of manual ISO-2022 switching.
272    
273     Why do italic characters look as if clipped?
274     Many fonts have difficulties with italic characters and hinting. For
275     example, the otherwise very nicely hinted font "xft:Bitstream Vera Sans
276     Mono" completely fails in its italic face. A workaround might be to
277     enable freetype autohinting, i.e. like this:
278    
279     URxvt.italicFont: xft:Bitstream Vera Sans Mono:italic:autohint=true
280     URxvt.boldItalicFont: xft:Bitstream Vera Sans Mono:bold:italic:autohint=true
281    
282     Can I speed up Xft rendering somehow?
283     Yes, the most obvious way to speed it up is to avoid Xft entirely, as it
284     is simply slow. If you still want Xft fonts you might try to disable
285     antialiasing (by appending ":antialias=false"), which saves lots of
286     memory and also speeds up rendering considerably.
287    
288     Rxvt-unicode doesn't seem to anti-alias its fonts, what is wrong?
289     Rxvt-unicode will use whatever you specify as a font. If it needs to
290     fall back to its default font search list it will prefer X11 core fonts,
291     because they are small and fast, and then use Xft fonts. It has
292     antialiasing disabled for most of them, because the author thinks they
293     look best that way.
294    
295     If you want antialiasing, you have to specify the fonts manually.
296    
297     What's with this bold/blink stuff?
298     If no bold colour is set via "colorBD:", bold will invert text using the
299     standard foreground colour.
300    
301     For the standard background colour, blinking will actually make the text
302     blink when compiled with "--enable-blinking". with standard colours.
303     Without "--enable-blinking", the blink attribute will be ignored.
304    
305     On ANSI colours, bold/blink attributes are used to set high-intensity
306     foreground/background colors.
307    
308     color0-7 are the low-intensity colors.
309    
310     color8-15 are the corresponding high-intensity colors.
311    
312     I don't like the screen colors. How do I change them?
313     You can change the screen colors at run-time using ~/.Xdefaults
314     resources (or as long-options).
315    
316     Here are values that are supposed to resemble a VGA screen, including
317     the murky brown that passes for low-intensity yellow:
318    
319     URxvt.color0: #000000
320     URxvt.color1: #A80000
321     URxvt.color2: #00A800
322     URxvt.color3: #A8A800
323     URxvt.color4: #0000A8
324     URxvt.color5: #A800A8
325     URxvt.color6: #00A8A8
326     URxvt.color7: #A8A8A8
327    
328     URxvt.color8: #000054
329     URxvt.color9: #FF0054
330     URxvt.color10: #00FF54
331     URxvt.color11: #FFFF54
332     URxvt.color12: #0000FF
333     URxvt.color13: #FF00FF
334     URxvt.color14: #00FFFF
335     URxvt.color15: #FFFFFF
336    
337     And here is a more complete set of non-standard colors.
338    
339     URxvt.cursorColor: #dc74d1
340     URxvt.pointerColor: #dc74d1
341     URxvt.background: #0e0e0e
342     URxvt.foreground: #4ad5e1
343     URxvt.color0: #000000
344     URxvt.color8: #8b8f93
345     URxvt.color1: #dc74d1
346     URxvt.color9: #dc74d1
347     URxvt.color2: #0eb8c7
348     URxvt.color10: #0eb8c7
349     URxvt.color3: #dfe37e
350     URxvt.color11: #dfe37e
351     URxvt.color5: #9e88f0
352     URxvt.color13: #9e88f0
353     URxvt.color6: #73f7ff
354     URxvt.color14: #73f7ff
355     URxvt.color7: #e1dddd
356     URxvt.color15: #e1dddd
357    
358     They have been described (not by me) as "pretty girly".
359    
360     Why do some characters look so much different than others?
361     See next entry.
362    
363     How does rxvt-unicode choose fonts?
364     Most fonts do not contain the full range of Unicode, which is fine.
365     Chances are that the font you (or the admin/package maintainer of your
366     system/os) have specified does not cover all the characters you want to
367     display.
368    
369     rxvt-unicode makes a best-effort try at finding a replacement font.
370     Often the result is fine, but sometimes the chosen font looks
371     bad/ugly/wrong. Some fonts have totally strange characters that don't
372     resemble the correct glyph at all, and rxvt-unicode lacks the artificial
373     intelligence to detect that a specific glyph is wrong: it has to believe
374     the font that the characters it claims to contain indeed look correct.
375    
376     In that case, select a font of your taste and add it to the font list,
377     e.g.:
378    
379     urxvt -fn basefont,font2,font3...
380    
381     When rxvt-unicode sees a character, it will first look at the base font.
382     If the base font does not contain the character, it will go to the next
383     font, and so on. Specifying your own fonts will also speed up this
384     search and use less resources within rxvt-unicode and the X-server.
385    
386     The only limitation is that none of the fonts may be larger than the
387     base font, as the base font defines the terminal character cell size,
388     which must be the same due to the way terminals work.
389    
390     Why do some chinese characters look so different than others?
391     This is because there is a difference between script and language --
392     rxvt-unicode does not know which language the text that is output is, as
393     it only knows the unicode character codes. If rxvt-unicode first sees a
394     japanese/chinese character, it might choose a japanese font for display.
395     Subsequent japanese characters will use that font. Now, many chinese
396     characters aren't represented in japanese fonts, so when the first
397     non-japanese character comes up, rxvt-unicode will look for a chinese
398     font -- unfortunately at this point, it will still use the japanese font
399     for chinese characters that are also in the japanese font.
400    
401     The workaround is easy: just tag a chinese font at the end of your font
402     list (see the previous question). The key is to view the font list as a
403     preference list: If you expect more japanese, list a japanese font
404     first. If you expect more chinese, put a chinese font first.
405    
406     In the future it might be possible to switch language preferences at
407     runtime (the internal data structure has no problem with using different
408     fonts for the same character at the same time, but no interface for this
409     has been designed yet).
410    
411     Until then, you might get away with switching fonts at runtime (see "Can
412     I switch the fonts at runtime?" later in this document).
413    
414 root 1.50 How can I make mplayer display video correctly?
415     We are working on it, in the meantime, as a workaround, use something
416     like:
417    
418     urxvt -b 600 -geometry 20x1 -e sh -c 'mplayer -wid $WINDOWID file...'
419    
420 root 1.42 Keyboard, Mouse & User Interaction
421     The new selection selects pieces that are too big, how can I select single words?
422     If you want to select e.g. alphanumeric words, you can use the following
423     setting:
424    
425     URxvt.selection.pattern-0: ([[:word:]]+)
426    
427     If you click more than twice, the selection will be extended more and
428     more.
429    
430     To get a selection that is very similar to the old code, try this
431     pattern:
432    
433     URxvt.selection.pattern-0: ([^"&'()*,;<=>?@[\\\\]^`{|})]+)
434    
435     Please also note that the *LeftClick Shift-LeftClik* combination also
436     selects words like the old code.
437    
438     I don't like the new selection/popups/hotkeys/perl, how do I change/disable it?
439     You can disable the perl extension completely by setting the
440     perl-ext-common resource to the empty string, which also keeps
441     rxvt-unicode from initialising perl, saving memory.
442    
443     If you only want to disable specific features, you first have to
444     identify which perl extension is responsible. For this, read the section
445     PREPACKAGED EXTENSIONS in the urxvtperl(3) manpage. For example, to
446     disable the selection-popup and option-popup, specify this
447     perl-ext-common resource:
448    
449     URxvt.perl-ext-common: default,-selection-popup,-option-popup
450    
451     This will keep the default extensions, but disable the two popup
452     extensions. Some extensions can also be configured, for example,
453     scrollback search mode is triggered by M-s. You can move it to any other
454     combination either by setting the searchable-scrollback resource:
455    
456     URxvt.searchable-scrollback: CM-s
457    
458     The cursor moves when selecting text in the current input line, how do I switch this off?
459     See next entry.
460    
461     During rlogin/ssh/telnet/etc. sessions, clicking near the cursor outputs strange escape sequences, how do I fix this?
462     These are caused by the "readline" perl extension. Under normal
463     circumstances, it will move your cursor around when you click into the
464     line that contains it. It tries hard not to do this at the wrong moment,
465     but when running a program that doesn't parse cursor movements or in
466     some cases during rlogin sessions, it fails to detect this properly.
467    
468 root 1.43 You can permanently switch this feature off by disabling the "readline"
469 root 1.42 extension:
470    
471     URxvt.perl-ext-common: default,-readline
472    
473     My numerical keypad acts weird and generates differing output?
474     Some Debian GNUL/Linux users seem to have this problem, although no
475     specific details were reported so far. It is possible that this is
476 root 1.43 caused by the wrong "TERM" setting, although the details of whether and
477 root 1.42 how this can happen are unknown, as "TERM=rxvt" should offer a
478     compatible keymap. See the answer to the previous question, and please
479     report if that helped.
480    
481     My Compose (Multi_key) key is no longer working.
482     The most common causes for this are that either your locale is not set
483     correctly, or you specified a preeditStyle that is not supported by your
484     input method. For example, if you specified OverTheSpot and your input
485     method (e.g. the default input method handling Compose keys) does not
486     support this (for instance because it is not visual), then rxvt-unicode
487     will continue without an input method.
488    
489     In this case either do not specify a preeditStyle or specify more than
490     one pre-edit style, such as OverTheSpot,Root,None.
491    
492     I cannot type "Ctrl-Shift-2" to get an ASCII NUL character due to ISO 14755
493     Either try "Ctrl-2" alone (it often is mapped to ASCII NUL even on
494     international keyboards) or simply use ISO 14755 support to your
495     advantage, typing <Ctrl-Shift-0> to get a ASCII NUL. This works for
496     other codes, too, such as "Ctrl-Shift-1-d" to type the default telnet
497     escape character and so on.
498    
499     Mouse cut/paste suddenly no longer works.
500     Make sure that mouse reporting is actually turned off since killing some
501     editors prematurely may leave the mouse in mouse report mode. I've heard
502     that tcsh may use mouse reporting unless it otherwise specified. A quick
503     check is to see if cut/paste works when the Alt or Shift keys are
504     depressed.
505    
506     What's with the strange Backspace/Delete key behaviour?
507 root 1.43 Assuming that the physical Backspace key corresponds to the Backspace
508 root 1.42 keysym (not likely for Linux ... see the following question) there are
509     two standard values that can be used for Backspace: "^H" and "^?".
510    
511     Historically, either value is correct, but rxvt-unicode adopts the
512 root 1.47 debian policy of using "^?" when unsure, because it's the one and only
513 root 1.42 correct choice :).
514    
515     Rxvt-unicode tries to inherit the current stty settings and uses the
516     value of `erase' to guess the value for backspace. If rxvt-unicode
517     wasn't started from a terminal (say, from a menu or by remote shell),
518     then the system value of `erase', which corresponds to CERASE in
519     <termios.h>, will be used (which may not be the same as your stty
520     setting).
521    
522     For starting a new rxvt-unicode:
523    
524     # use Backspace = ^H
525     $ stty erase ^H
526     $ urxvt
527    
528     # use Backspace = ^?
529     $ stty erase ^?
530     $ urxvt
531    
532     Toggle with "ESC [ 36 h" / "ESC [ 36 l".
533    
534     For an existing rxvt-unicode:
535    
536     # use Backspace = ^H
537     $ stty erase ^H
538     $ echo -n "^[[36h"
539    
540     # use Backspace = ^?
541     $ stty erase ^?
542     $ echo -n "^[[36l"
543    
544     This helps satisfy some of the Backspace discrepancies that occur, but
545     if you use Backspace = "^H", make sure that the termcap/terminfo value
546     properly reflects that.
547    
548     The Delete key is a another casualty of the ill-defined Backspace
549     problem. To avoid confusion between the Backspace and Delete keys, the
550     Delete key has been assigned an escape sequence to match the vt100 for
551     Execute ("ESC [ 3 ~") and is in the supplied termcap/terminfo.
552    
553     Some other Backspace problems:
554    
555     some editors use termcap/terminfo, some editors (vim I'm told) expect
556     Backspace = ^H, GNU Emacs (and Emacs-like editors) use ^H for help.
557    
558     Perhaps someday this will all be resolved in a consistent manner.
559    
560     I don't like the key-bindings. How do I change them?
561     There are some compile-time selections available via configure. Unless
562     you have run "configure" with the "--disable-resources" option you can
563     use the `keysym' resource to alter the keystrings associated with
564     keysyms.
565    
566     Here's an example for a URxvt session started using "urxvt -name URxvt"
567    
568     URxvt.keysym.Home: \033[1~
569     URxvt.keysym.End: \033[4~
570     URxvt.keysym.C-apostrophe: \033<C-'>
571     URxvt.keysym.C-slash: \033<C-/>
572     URxvt.keysym.C-semicolon: \033<C-;>
573     URxvt.keysym.C-grave: \033<C-`>
574     URxvt.keysym.C-comma: \033<C-,>
575     URxvt.keysym.C-period: \033<C-.>
576     URxvt.keysym.C-0x60: \033<C-`>
577     URxvt.keysym.C-Tab: \033<C-Tab>
578     URxvt.keysym.C-Return: \033<C-Return>
579     URxvt.keysym.S-Return: \033<S-Return>
580     URxvt.keysym.S-space: \033<S-Space>
581     URxvt.keysym.M-Up: \033<M-Up>
582     URxvt.keysym.M-Down: \033<M-Down>
583     URxvt.keysym.M-Left: \033<M-Left>
584     URxvt.keysym.M-Right: \033<M-Right>
585     URxvt.keysym.M-C-0: list \033<M-C- 0123456789 >
586     URxvt.keysym.M-C-a: list \033<M-C- abcdefghijklmnopqrstuvwxyz >
587     URxvt.keysym.F12: command:\033]701;zh_CN.GBK\007
588    
589     See some more examples in the documentation for the keysym resource.
590    
591     I'm using keyboard model XXX that has extra Prior/Next/Insert keys. How do I make use of them? For example, the Sun Keyboard type 4 has the following map
592     KP_Insert == Insert
593     F22 == Print
594     F27 == Home
595     F29 == Prior
596     F33 == End
597     F35 == Next
598    
599     Rather than have rxvt-unicode try to accommodate all the various
600     possible keyboard mappings, it is better to use `xmodmap' to remap the
601     keys as required for your particular machine.
602    
603     Terminal Configuration
604     Can I see a typical configuration?
605     The default configuration tries to be xterm-like, which I don't like
606     that much, but it's least surprise to regular users.
607    
608     As a rxvt or rxvt-unicode user, you are practically supposed to invest
609     time into customising your terminal. To get you started, here is the
610     author's .Xdefaults entries, with comments on what they do. It's
611     certainly not *typical*, but what's typical...
612    
613     URxvt.cutchars: "()*,<>[]{}|'
614     URxvt.print-pipe: cat >/tmp/xxx
615    
616     These are just for testing stuff.
617    
618     URxvt.imLocale: ja_JP.UTF-8
619     URxvt.preeditType: OnTheSpot,None
620    
621     This tells rxvt-unicode to use a special locale when communicating with
622     the X Input Method, and also tells it to only use the OnTheSpot pre-edit
623     type, which requires the "xim-onthespot" perl extension but rewards me
624     with correct-looking fonts.
625    
626     URxvt.perl-lib: /root/lib/urxvt
627     URxvt.perl-ext-common: default,selection-autotransform,selection-pastebin,xim-onthespot,remote-clipboard
628     URxvt.selection.pattern-0: ( at .*? line \\d+)
629     URxvt.selection.pattern-1: ^(/[^:]+):\
630     URxvt.selection-autotransform.0: s/^([^:[:space:]]+):(\\d+):?$/:e \\Q$1\\E\\x0d:$2\\x0d/
631     URxvt.selection-autotransform.1: s/^ at (.*?) line (\\d+)$/:e \\Q$1\\E\\x0d:$2\\x0d/
632    
633     This is my perl configuration. The first two set the perl library
634     directory and also tells urxvt to use a large number of extensions. I
635     develop for myself mostly, so I actually use most of the extensions I
636     write.
637    
638     The selection stuff mainly makes the selection perl-error-message aware
639 root 1.43 and tells it to convert perl error messages into vi-commands to load the
640 root 1.42 relevant file and go tot he error line number.
641    
642     URxvt.scrollstyle: plain
643     URxvt.secondaryScroll: true
644    
645     As the documentation says: plain is the preferred scrollbar for the
646 root 1.43 author. The "secondaryScroll" configures urxvt to scroll in full-screen
647     apps, like screen, so lines scrolled out of screen end up in urxvt's
648 root 1.42 scrollback buffer.
649    
650     URxvt.background: #000000
651     URxvt.foreground: gray90
652     URxvt.color7: gray90
653     URxvt.colorBD: #ffffff
654     URxvt.cursorColor: #e0e080
655     URxvt.throughColor: #8080f0
656     URxvt.highlightColor: #f0f0f0
657    
658     Some colours. Not sure which ones are being used or even non-defaults,
659     but these are in my .Xdefaults. Most notably, they set
660     foreground/background to light gray/black, and also make sure that the
661     colour 7 matches the default foreground colour.
662    
663     URxvt.underlineColor: yellow
664    
665     Another colour, makes underline lines look different. Sometimes hurts,
666     but is mostly a nice effect.
667    
668     URxvt.geometry: 154x36
669     URxvt.loginShell: false
670     URxvt.meta: ignore
671     URxvt.utmpInhibit: true
672    
673     Uh, well, should be mostly self-explanatory. By specifying some defaults
674     manually, I can quickly switch them for testing.
675    
676     URxvt.saveLines: 8192
677    
678     A large scrollback buffer is essential. Really.
679    
680     URxvt.mapAlert: true
681    
682     The only case I use it is for my IRC window, which I like to keep
683     iconified till people msg me (which beeps).
684    
685     URxvt.visualBell: true
686    
687     The audible bell is often annoying, especially when in a crowd.
688    
689     URxvt.insecure: true
690    
691     Please don't hack my mutt! Ooops...
692    
693     URxvt.pastableTabs: false
694    
695     I once thought this is a great idea.
696    
697     urxvt.font: 9x15bold,\
698     -misc-fixed-bold-r-normal--15-140-75-75-c-90-iso10646-1,\
699     -misc-fixed-medium-r-normal--15-140-75-75-c-90-iso10646-1, \
700     [codeset=JISX0208]xft:Kochi Gothic, \
701     xft:Bitstream Vera Sans Mono:autohint=true, \
702     xft:Code2000:antialias=false
703     urxvt.boldFont: -xos4-terminus-bold-r-normal--14-140-72-72-c-80-iso8859-15
704     urxvt.italicFont: xft:Bitstream Vera Sans Mono:italic:autohint=true
705     urxvt.boldItalicFont: xft:Bitstream Vera Sans Mono:bold:italic:autohint=true
706    
707     I wrote rxvt-unicode to be able to specify fonts exactly. So don't be
708 root 1.43 overwhelmed. A special note: the "9x15bold" mentioned above is actually
709 root 1.42 the version from XFree-3.3, as XFree-4 replaced it by a totally
710     different font (different glyphs for ";" and many other harmless
711     characters), while the second font is actually the "9x15bold" from
712     XFree4/XOrg. The bold version has less chars than the medium version, so
713 root 1.43 I use it for rare characters, too. When editing sources with vim, I use
714 root 1.42 italic for comments and other stuff, which looks quite good with
715     Bitstream Vera anti-aliased.
716    
717     Terminus is a quite bad font (many very wrong glyphs), but for most of
718     my purposes, it works, and gives a different look, as my normal
719     (Non-bold) font is already bold, and I want to see a difference between
720     bold and normal fonts.
721    
722     Please note that I used the "urxvt" instance name and not the "URxvt"
723     class name. Thats because I use different configs for different
724     purposes, for example, my IRC window is started with "-name IRC", and
725     uses these defaults:
726    
727     IRC*title: IRC
728     IRC*geometry: 87x12+535+542
729     IRC*saveLines: 0
730     IRC*mapAlert: true
731     IRC*font: suxuseuro
732     IRC*boldFont: suxuseuro
733     IRC*colorBD: white
734     IRC*keysym.M-C-1: command:\033]710;suxuseuro\007\033]711;suxuseuro\007
735     IRC*keysym.M-C-2: command:\033]710;9x15bold\007\033]711;9x15bold\007
736    
737     "Alt-Shift-1" and "Alt-Shift-2" switch between two different font sizes.
738     "suxuseuro" allows me to keep an eye (and actually read) stuff while
739     keeping a very small window. If somebody pastes something complicated
740     (e.g. japanese), I temporarily switch to a larger font.
741    
742     The above is all in my ".Xdefaults" (I don't use ".Xresources" nor
743     "xrdb"). I also have some resources in a separate ".Xdefaults-hostname"
744     file for different hosts, for example, on ym main desktop, I use:
745    
746     URxvt.keysym.C-M-q: command:\033[3;5;5t
747     URxvt.keysym.C-M-y: command:\033[3;5;606t
748     URxvt.keysym.C-M-e: command:\033[3;1605;5t
749     URxvt.keysym.C-M-c: command:\033[3;1605;606t
750     URxvt.keysym.C-M-p: perl:test
751    
752     The first for keysym definitions allow me to quickly bring some windows
753     in the layout I like most. Ion users might start laughing but will stop
754     immediately when I tell them that I use my own Fvwm2 module for much the
755     same effect as Ion provides, and I only very rarely use the above key
756     combinations :->
757    
758     Why doesn't rxvt-unicode read my resources?
759     Well, why, indeed? It does, in a way very similar to other X
760     applications. Most importantly, this means that if you or your OS loads
761     resources into the X display (the right way to do it), rxvt-unicode will
762     ignore any resource files in your home directory. It will only read
763     $HOME/.Xdefaults when no resources are attached to the display.
764    
765     If you have or use an $HOME/.Xresources file, chances are that resources
766     are loaded into your X-server. In this case, you have to re-login after
767     every change (or run xrdb -merge $HOME/.Xresources).
768    
769     Also consider the form resources have to use:
770    
771     URxvt.resource: value
772    
773     If you want to use another form (there are lots of different ways of
774 root 1.43 specifying resources), make sure you understand whether and why it
775     works. If unsure, use the form above.
776 root 1.42
777     When I log-in to another system it tells me about missing terminfo data?
778     The terminal description used by rxvt-unicode is not as widely available
779     as that for xterm, or even rxvt (for which the same problem often
780     arises).
781    
782     The correct solution for this problem is to install the terminfo, this
783 root 1.44 can be done like this (with ncurses' infocmp and works as user and
784     admin):
785 root 1.42
786     REMOTE=remotesystem.domain
787 root 1.44 infocmp rxvt-unicode | ssh $REMOTE "mkdir -p .terminfo && cat >/tmp/ti && tic /tmp/ti"
788 root 1.42
789     ... or by installing rxvt-unicode normally on the remote system,
790    
791 root 1.44 One some systems you might need to set $TERMINFO to the full path of
792     $HOME/.terminfo for this to work.
793    
794 root 1.42 If you cannot or do not want to do this, then you can simply set
795     "TERM=rxvt" or even "TERM=xterm", and live with the small number of
796     problems arising, which includes wrong keymapping, less and different
797     colours and some refresh errors in fullscreen applications. It's a nice
798     quick-and-dirty workaround for rare cases, though.
799    
800     If you always want to do this (and are fine with the consequences) you
801     can either recompile rxvt-unicode with the desired TERM value or use a
802     resource to set it:
803    
804     URxvt.termName: rxvt
805    
806     If you don't plan to use rxvt (quite common...) you could also replace
807     the rxvt terminfo file with the rxvt-unicode one and use "TERM=rxvt".
808    
809     "tic" outputs some error when compiling the terminfo entry.
810     Most likely it's the empty definition for "enacs=". Just replace it by
811     "enacs=\E[0@" and try again.
812    
813     "bash"'s readline does not work correctly under urxvt.
814     See next entry.
815    
816     I need a termcap file entry.
817     One reason you might want this is that some distributions or operating
818     systems still compile some programs using the long-obsoleted termcap
819     library (Fedora Core's bash is one example) and rely on a termcap entry
820     for "rxvt-unicode".
821    
822 root 1.43 You could use rxvt's termcap entry with reasonable results in many
823     cases. You can also create a termcap entry by using terminfo's infocmp
824     program like this:
825 root 1.42
826     infocmp -C rxvt-unicode
827    
828     Or you could use this termcap entry, generated by the command above:
829    
830     rxvt-unicode|rxvt-unicode terminal (X Window System):\
831     :am:bw:eo:km:mi:ms:xn:xo:\
832     :co#80:it#8:li#24:lm#0:\
833     :AL=\E[%dL:DC=\E[%dP:DL=\E[%dM:DO=\E[%dB:IC=\E[%d@:\
834     :K1=\EOw:K2=\EOu:K3=\EOy:K4=\EOq:K5=\EOs:LE=\E[%dD:\
835     :RI=\E[%dC:SF=\E[%dS:SR=\E[%dT:UP=\E[%dA:ae=\E(B:al=\E[L:\
836     :as=\E(0:bl=^G:cd=\E[J:ce=\E[K:cl=\E[H\E[2J:\
837     :cm=\E[%i%d;%dH:cr=^M:cs=\E[%i%d;%dr:ct=\E[3g:dc=\E[P:\
838     :dl=\E[M:do=^J:ec=\E[%dX:ei=\E[4l:ho=\E[H:\
839     :i1=\E[?47l\E=\E[?1l:ic=\E[@:im=\E[4h:\
840     :is=\E[r\E[m\E[2J\E[H\E[?7h\E[?1;3;4;6l\E[4l:\
841     :k1=\E[11~:k2=\E[12~:k3=\E[13~:k4=\E[14~:k5=\E[15~:\
842     :k6=\E[17~:k7=\E[18~:k8=\E[19~:k9=\E[20~:kD=\E[3~:\
843     :kI=\E[2~:kN=\E[6~:kP=\E[5~:kb=\177:kd=\EOB:ke=\E[?1l\E>:\
844     :kh=\E[7~:kl=\EOD:kr=\EOC:ks=\E[?1h\E=:ku=\EOA:le=^H:\
845     :mb=\E[5m:md=\E[1m:me=\E[m\017:mr=\E[7m:nd=\E[C:rc=\E8:\
846     :sc=\E7:se=\E[27m:sf=^J:so=\E[7m:sr=\EM:st=\EH:ta=^I:\
847     :te=\E[r\E[?1049l:ti=\E[?1049h:ue=\E[24m:up=\E[A:\
848     :us=\E[4m:vb=\E[?5h\E[?5l:ve=\E[?25h:vi=\E[?25l:\
849     :vs=\E[?25h:
850    
851     Why does "ls" no longer have coloured output?
852     The "ls" in the GNU coreutils unfortunately doesn't use terminfo to
853 root 1.43 decide whether a terminal has colour, but uses its own configuration
854 root 1.42 file. Needless to say, "rxvt-unicode" is not in its default file (among
855     with most other terminals supporting colour). Either add:
856    
857     TERM rxvt-unicode
858    
859     to "/etc/DIR_COLORS" or simply add:
860    
861     alias ls='ls --color=auto'
862    
863     to your ".profile" or ".bashrc".
864    
865     Why doesn't vim/emacs etc. use the 88 colour mode?
866     See next entry.
867    
868     Why doesn't vim/emacs etc. make use of italic?
869     See next entry.
870    
871     Why are the secondary screen-related options not working properly?
872     Make sure you are using "TERM=rxvt-unicode". Some pre-packaged
873     distributions (most notably Debian GNU/Linux) break rxvt-unicode by
874     setting "TERM" to "rxvt", which doesn't have these extra features.
875     Unfortunately, some of these (most notably, again, Debian GNU/Linux)
876     furthermore fail to even install the "rxvt-unicode" terminfo file, so
877     you will need to install it on your own (See the question When I log-in
878     to another system it tells me about missing terminfo data? on how to do
879     this).
880    
881     Encoding / Locale / Input Method Issues
882     Rxvt-unicode does not seem to understand the selected encoding?
883     See next entry.
884    
885     Unicode does not seem to work?
886     If you encounter strange problems like typing an accented character but
887     getting two unrelated other characters or similar, or if program output
888     is subtly garbled, then you should check your locale settings.
889    
890     Rxvt-unicode must be started with the same "LC_CTYPE" setting as the
891 root 1.46 programs running in it. Often rxvt-unicode is started in the "C" locale,
892     while the login script running within the rxvt-unicode window changes
893     the locale to something else, e.g. "en_GB.UTF-8". Needless to say, this
894     is not going to work, and is the most common cause for problems.
895 root 1.42
896     The best thing is to fix your startup environment, as you will likely
897     run into other problems. If nothing works you can try this in your
898     .profile.
899    
900 root 1.46 printf '\33]701;%s\007' "$LC_CTYPE" # $LANG or $LC_ALL are worth a try, too
901 root 1.42
902     If this doesn't work, then maybe you use a "LC_CTYPE" specification not
903     supported on your systems. Some systems have a "locale" command which
904     displays this (also, "perl -e0" can be used to check locale settings, as
905     it will complain loudly if it cannot set the locale). If it displays
906     something like:
907    
908     locale: Cannot set LC_CTYPE to default locale: ...
909    
910     Then the locale you specified is not supported on your system.
911    
912     If nothing works and you are sure that everything is set correctly then
913     you will need to remember a little known fact: Some programs just don't
914     support locales :(
915    
916     How does rxvt-unicode determine the encoding to use?
917     See next entry.
918    
919     Is there an option to switch encodings?
920     Unlike some other terminals, rxvt-unicode has no encoding switch, and no
921     specific "utf-8" mode, such as xterm. In fact, it doesn't even know
922     about UTF-8 or any other encodings with respect to terminal I/O.
923    
924     The reasons is that there exists a perfectly fine mechanism for
925     selecting the encoding, doing I/O and (most important) communicating
926     this to all applications so everybody agrees on character properties
927     such as width and code number. This mechanism is the *locale*.
928     Applications not using that info will have problems (for example,
929     "xterm" gets the width of characters wrong as it uses its own,
930     locale-independent table under all locales).
931    
932     Rxvt-unicode uses the "LC_CTYPE" locale category to select encoding. All
933     programs doing the same (that is, most) will automatically agree in the
934     interpretation of characters.
935    
936     Unfortunately, there is no system-independent way to select locales, nor
937     is there a standard on how locale specifiers will look like.
938    
939     On most systems, the content of the "LC_CTYPE" environment variable
940     contains an arbitrary string which corresponds to an already-installed
941     locale. Common names for locales are "en_US.UTF-8", "de_DE.ISO-8859-15",
942     "ja_JP.EUC-JP", i.e. "language_country.encoding", but other forms (i.e.
943     "de" or "german") are also common.
944    
945     Rxvt-unicode ignores all other locale categories, and except for the
946     encoding, ignores country or language-specific settings, i.e.
947     "de_DE.UTF-8" and "ja_JP.UTF-8" are the normally same to rxvt-unicode.
948    
949     If you want to use a specific encoding you have to make sure you start
950     rxvt-unicode with the correct "LC_CTYPE" category.
951    
952     Can I switch locales at runtime?
953     Yes, using an escape sequence. Try something like this, which sets
954     rxvt-unicode's idea of "LC_CTYPE".
955    
956     printf '\33]701;%s\007' ja_JP.SJIS
957    
958     See also the previous answer.
959    
960     Sometimes this capability is rather handy when you want to work in one
961     locale (e.g. "de_DE.UTF-8") but some programs don't support it (e.g.
962     UTF-8). For example, I use this script to start "xjdic", which first
963     switches to a locale supported by xjdic and back later:
964    
965     printf '\33]701;%s\007' ja_JP.SJIS
966     xjdic -js
967     printf '\33]701;%s\007' de_DE.UTF-8
968    
969     You can also use xterm's "luit" program, which usually works fine,
970     except for some locales where character width differs between program-
971     and rxvt-unicode-locales.
972    
973     I have problems getting my input method working.
974     Try a search engine, as this is slightly different for every input
975     method server.
976    
977     Here is a checklist:
978    
979     - Make sure your locale *and* the imLocale are supported on your OS.
980     Try "locale -a" or check the documentation for your OS.
981    
982     - Make sure your locale or imLocale matches a locale supported by your
983     XIM.
984     For example, kinput2 does not support UTF-8 locales, you should use
985     "ja_JP.EUC-JP" or equivalent.
986    
987     - Make sure your XIM server is actually running.
988     - Make sure the "XMODIFIERS" environment variable is set correctly when
989     *starting* rxvt-unicode.
990     When you want to use e.g. kinput2, it must be set to "@im=kinput2".
991 root 1.43 For scim, use "@im=SCIM". You can see what input method servers are
992 root 1.42 running with this command:
993    
994     xprop -root XIM_SERVERS
995    
996 root 1.44 *
997 root 1.42
998     My input method wants <some encoding> but I want UTF-8, what can I do?
999     You can specify separate locales for the input method and the rest of
1000     the terminal, using the resource "imlocale":
1001    
1002     URxvt.imlocale: ja_JP.EUC-JP
1003    
1004     Now you can start your terminal with "LC_CTYPE=ja_JP.UTF-8" and still
1005     use your input method. Please note, however, that, depending on your
1006     Xlib version, you may not be able to input characters outside "EUC-JP"
1007     in a normal way then, as your input method limits you.
1008    
1009     Rxvt-unicode crashes when the X Input Method changes or exits.
1010     Unfortunately, this is unavoidable, as the XIM protocol is racy by
1011     design. Applications can avoid some crashes at the expense of memory
1012     leaks, and Input Methods can avoid some crashes by careful ordering at
1013     exit time. kinput2 (and derived input methods) generally succeeds, while
1014     SCIM (or similar input methods) fails. In the end, however, crashes
1015     cannot be completely avoided even if both sides cooperate.
1016    
1017     So the only workaround is not to kill your Input Method Servers.
1018    
1019     Operating Systems / Package Maintaining
1020     I am using Debian GNU/Linux and have a problem...
1021     The Debian GNU/Linux package of rxvt-unicode in sarge contains large
1022     patches that considerably change the behaviour of rxvt-unicode (but
1023     unfortunately this notice has been removed). Before reporting a bug to
1024     the original rxvt-unicode author please download and install the genuine
1025     version (<http://software.schmorp.de#rxvt-unicode>) and try to reproduce
1026     the problem. If you cannot, chances are that the problems are specific
1027     to Debian GNU/Linux, in which case it should be reported via the Debian
1028     Bug Tracking System (use "reportbug" to report the bug).
1029    
1030     For other problems that also affect the Debian package, you can and
1031     probably should use the Debian BTS, too, because, after all, it's also a
1032     bug in the Debian version and it serves as a reminder for other users
1033     that might encounter the same issue.
1034    
1035     I am maintaining rxvt-unicode for distribution/OS XXX, any recommendation?
1036     You should build one binary with the default options. configure now
1037     enables most useful options, and the trend goes to making them
1038 root 1.43 runtime-switchable, too, so there is usually no drawback to enabling
1039 root 1.42 them, except higher disk and possibly memory usage. The perl interpreter
1040     should be enabled, as important functionality (menus, selection, likely
1041     more in the future) depends on it.
1042    
1043     You should not overwrite the "perl-ext-common" snd "perl-ext" resources
1044     system-wide (except maybe with "defaults"). This will result in useful
1045     behaviour. If your distribution aims at low memory, add an empty
1046     "perl-ext-common" resource to the app-defaults file. This will keep the
1047     perl interpreter disabled until the user enables it.
1048    
1049     If you can/want build more binaries, I recommend building a minimal one
1050     with "--disable-everything" (very useful) and a maximal one with
1051     "--enable-everything" (less useful, it will be very big due to a lot of
1052     encodings built-in that increase download times and are rarely used).
1053    
1054     I need to make it setuid/setgid to support utmp/ptys on my OS, is this safe?
1055     It should be, starting with release 7.1. You are encouraged to properly
1056     install urxvt with privileges necessary for your OS now.
1057    
1058     When rxvt-unicode detects that it runs setuid or setgid, it will fork
1059     into a helper process for privileged operations (pty handling on some
1060     systems, utmp/wtmp/lastlog handling on others) and drop privileges
1061     immediately. This is much safer than most other terminals that keep
1062     privileges while running (but is more relevant to urxvt, as it contains
1063     things as perl interpreters, which might be "helpful" to attackers).
1064    
1065     This forking is done as the very first within main(), which is very
1066     early and reduces possible bugs to initialisation code run before
1067     main(), or things like the dynamic loader of your system, which should
1068     result in very little risk.
1069    
1070     I am on FreeBSD and rxvt-unicode does not seem to work at all.
1071     Rxvt-unicode requires the symbol "__STDC_ISO_10646__" to be defined in
1072     your compile environment, or an implementation that implements it,
1073 root 1.43 whether it defines the symbol or not. "__STDC_ISO_10646__" requires that
1074 root 1.42 wchar_t is represented as unicode.
1075    
1076 root 1.43 As you might have guessed, FreeBSD does neither define this symbol nor
1077 root 1.42 does it support it. Instead, it uses its own internal representation of
1078     wchar_t. This is, of course, completely fine with respect to standards.
1079    
1080     However, that means rxvt-unicode only works in "POSIX", "ISO-8859-1" and
1081     "UTF-8" locales under FreeBSD (which all use Unicode as wchar_t.
1082    
1083     "__STDC_ISO_10646__" is the only sane way to support multi-language apps
1084     in an OS, as using a locale-dependent (and non-standardized)
1085     representation of wchar_t makes it impossible to convert between wchar_t
1086     (as used by X11 and your applications) and any other encoding without
1087     implementing OS-specific-wrappers for each and every locale. There
1088     simply are no APIs to convert wchar_t into anything except the current
1089     locale encoding.
1090    
1091     Some applications (such as the formidable mlterm) work around this by
1092     carrying their own replacement functions for character set handling with
1093     them, and either implementing OS-dependent hacks or doing multiple
1094     conversions (which is slow and unreliable in case the OS implements
1095     encodings slightly different than the terminal emulator).
1096    
1097     The rxvt-unicode author insists that the right way to fix this is in the
1098     system libraries once and for all, instead of forcing every app to carry
1099     complete replacements for them :)
1100    
1101     How can I use rxvt-unicode under cygwin?
1102     rxvt-unicode should compile and run out of the box on cygwin, using the
1103     X11 libraries that come with cygwin. libW11 emulation is no longer
1104     supported (and makes no sense, either, as it only supported a single
1105     font). I recommend starting the X-server in "-multiwindow" or
1106     "-rootless" mode instead, which will result in similar look&feel as the
1107     old libW11 emulation.
1108    
1109     At the time of this writing, cygwin didn't seem to support any
1110     multi-byte encodings (you might try "LC_CTYPE=C-UTF-8"), so you are
1111     likely limited to 8-bit encodings.
1112    
1113 root 1.49 Character widths are not correct.
1114     urxvt uses the system wcwidth function to know the information about the
1115     width of characters, so on systems with incorrect locale data you will
1116     likely get bad results. Two notorious examples are Solaris 9, where
1117     single-width characters like U+2514 are reported as double-width, and
1118     Darwin 8, where combining chars are reported having width 1.
1119    
1120     The solution is to upgrade your system or switch to a better one. A
1121     possibly working workaround is to use a wcwidth implementation like
1122    
1123     http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
1124