1 The Linux keyboard and console HOWTO
2 Andries Brouwer, aeb@cwi.nl
5 This note contains some information about the Linux keyboard and con-
6 sole, and the use of non-ASCII characters. It describes Linux 2.0.
7 ______________________________________________________________________
69 2. Keyboard generalities
71 3. Console generalities
73 4. Resetting your terminal
75 4.1 Keyboard hardware reset
77 5. Delete and Backspace
79 5.1 How to tell Unix what character you want to use to delete the last typed character
80 5.1.1 `Getty used to do the right thing with DEL and BS but is broken now?'
81 5.1.2 `Login behaves differently at the first and second login attempts?'
82 5.2 How to tell Linux what code to generate when a key is pressed
83 5.2.1 `Why doesn't the Backspace key generate BackSpace by default?'
84 5.3 How to tell X to interchange Delete and Backspace
85 5.4 How to tell emacs what to do when it receives a Delete or Backspace
86 5.5 How to tell emacs to interchange Delete and Backspace
87 5.6 How to tell kermit to interchange Delete and Backspace
88 5.7 How to tell xterm to interchange Delete and Backspace
89 5.8 How to tell xterm about your favourite tty modes
90 5.9 How to tell xmosaic that the Backspace key generates a DEL
91 5.10 A better solution for Motif-using programs, like netscape
92 5.11 What about termcap and terminfo?
93 5.12 A complete solution
95 6. The console character sets
99 7.1 Changing the number of Virtual Consoles
101 8. Ctrl-Alt-Del and other special key combinations
103 8.1 Ctrl-Alt-Del (Boot)
104 8.2 Other combinations
106 8.4 Dosemu Combinations
107 8.5 Composing symbols
110 9. How to get out of raw mode
112 10. The keyboard LEDs
114 11. The TERM variable
118 12. How to make other programs work with non-ASCII chars
122 13.1 What precisely does XFree86-2.1 do when it initializes its keymap?
124 14. Unusual keys and keyboards
126 15. Examples of use of loadkeys and xmodmap
128 15.1 `I can use only one finger to type with'
130 16. Changing the video mode
132 16.1 Instructions for the use of resizecons
133 17. Changing the keyboard repeat rate
141 21. Some properties of the VT100 - application key mode
143 22. Hardware incompatibility
149 ______________________________________________________________________
151 1
\b1.
\b. U
\bUs
\bse
\bef
\bfu
\bul
\bl p
\bpr
\bro
\bog
\bgr
\bra
\bam
\bms
\bs
154 The following packages contain keyboard or console related programs.
156 kbd-0.96.tar.gz contains loadkeys, dumpkeys, showkey, setmetamode,
157 setleds, setfont, showfont, mapscrn, kbd_mode, loadunimap, chvt,
158 resizecons, deallocvt, getkeycodes, setkeycodes.
160 util-linux-2.6 contains setterm, kbdrate. (Yes, the more in util-
161 linux-2.6 dumps core due to a name conflict. Preserve your old copy,
162 or use util-linux-2.5, or change `savetty' to `my_savetty' in more.c.)
164 sh-utils-1.12 contains stty.
166 open-1.4.tgz contains open (that should be renamed to openvt). (See
167 also dynamic-vc-1.1.tar.gz and consd-1.1.tgz.)
169 SVGATextMode-1.8.tar.gz contains SVGATextMode, a program that
170 obsoletes resizecons.
172 The X distribution contains xmodmap, xset, kbd_mode. (See also
173 X386keybd(1) for the situation under XFree86 1.3, and Xserver(1) for
174 the XKEYBOARD extension under X11R6.)
176 termcap-2.0.8.tar.gz contains termcap, an old terminal capabilities
177 data base. ncurses-1.9.9e.tar.gz contains the termlib data base which
178 obsoletes termcap. (However, there are still many programs using
181 See loadkeys(1), setleds(1) and setmetamode(1) for the codes generated
182 by the various keys and the setting of leds when not under X. Under X,
183 see xmodmap(1) and xset(1).
185 See setfont(8) for loading console fonts. Many people will want to
186 load a font like iso01.f16 because the default font is the hardware
187 font of the video card, and often is a `Code Page 437' font missing
188 accented characters and other Latin-1 symbols.
190 See setterm(1) and kbdrate(8) for properties such as foreground and
191 background colors, screen blanking and character repeat rate when not
192 under X. Under X, see xset(1), also for key click and bell volume.
194 The file /etc/termcap defines the escape sequences used by many
195 programs addressing the console (or any other terminal). See
196 termcap(5). A more modern version is found in /usr/lib/terminfo. See
197 terminfo(5). Terminfo files are compiled by the terminfo compiler
198 /usr/lib/terminfo/tic, see tic(1). Their contents can be examined
199 using the program infocmp, see infocmp(1). The Linux console
200 sequences are documented in console_codes(4).
204 2
\b2.
\b. K
\bKe
\bey
\byb
\bbo
\boa
\bar
\brd
\bd g
\bge
\ben
\bne
\ber
\bra
\bal
\bli
\bit
\bti
\bie
\bes
\bs
207 You press a key, and the keyboard controller sends scancodes to the
208 kernel keyboard driver. Some keyboards can be programmed, but usually
209 the scancodes corresponding to your keys are fixed. The kernel
210 keyboard driver just transmits whatever it receives to the application
211 program when it is in _
\bs_
\bc_
\ba_
\bn_
\bc_
\bo_
\bd_
\be _
\bm_
\bo_
\bd_
\be, like when X is running.
212 Otherwise, it parses the stream of scancodes into keycodes,
213 corresponding to key press or key release events. (A single key press
214 can generate up to 6 scancodes.) These keycodes are transmitted to
215 the application program when it is in _
\bk_
\be_
\by_
\bc_
\bo_
\bd_
\be _
\bm_
\bo_
\bd_
\be (as used, for
216 example, by showkey). Otherwise, these keycodes are looked up in the
217 keymap, and the character or string found there is transmitted to the
218 application, or the action described there is performed. (For
219 example, if one presses and releases the a key, then the keyboard
220 produces scancodes 0x1e and 0x9e, this is converted to keycodes 30 and
221 158, and then transmitted as 0141, the ASCII or latin-1 code for `a';
222 if one presses and releases Delete, then the keyboard produces
223 scancodes 0xe0 0x53 0xe0 0xd3, these are converted to keycodes 111 and
224 239, and then transmitted as the 4-symbol sequence ESC [ 3 ~, all
225 assuming a US keyboard and a default keymap. An example of a key
226 combination to which an action is assigned is Ctrl-Alt-Del.)
228 The translation between unusual scancodes and keycodes can be set
229 using the utility setkeycodes - only very few people will need it.
230 The translation between keycodes and characters or strings or actions,
231 that is, the keymap, is set using the utilities loadkeys and
232 setmetamode. For details, see getkeycodes(8), setkeycodes(8),
233 dumpkeys(1), loadkeys(1), setmetamode(1). The format of the files
234 output by dumpkeys and read by loadkeys is described in keymaps(5).
236 Where it says `transmitted to the application' in the above
237 description, this really means `transmitted to the terminal driver'.
238 That is, further processing is just like that of text that comes in
239 over a serial line. The details of this processing are set by the
243 3
\b3.
\b. C
\bCo
\bon
\bns
\bso
\bol
\ble
\be g
\bge
\ben
\bne
\ber
\bra
\bal
\bli
\bit
\bti
\bie
\bes
\bs
246 Conversely, when you output something to the console, it first
247 undergoes the standard tty processing, and then is fed to the console
248 driver. The console driver emulates a VT100, and parses the input in
249 order to recognize VT100 escape sequences (for cursor movement, clear
250 screen, etc.). The characters that are not part of an escape sequence
251 are first converted into Unicode, using one of four mapping tables if
252 the console was not in UTF-8 mode to start with, then looked up in the
253 table describing the correspondence between Unicode values and font
254 positions, and the obtained 8- or 9-bit font indices are then written
255 to video memory, where they cause the display of character shapes
256 found in the video card's character ROM. One can load one's own fonts
257 into character ROM using setfont, load the corresponding Unicode map
258 with loadunimap, and load a user mapping table using mapscrn. More
259 details will be given below.
261 There are many consoles (called _
\bV_
\bi_
\br_
\bt_
\bu_
\ba_
\bl _
\bC_
\bo_
\bn_
\bs_
\bo_
\bl_
\be_
\bs or _
\bV_
\bi_
\br_
\bt_
\bu_
\ba_
\bl _
\bT_
\be_
\br_
\bm_
\bi_
\bn_
\ba_
\bl_
\bs,
262 abbreviated VCs or VTs) that share the same screen. You can use them
263 as independent devices, either to run indendent login sessions, or
264 just to send some output to, perhaps from top, or the tail of the
265 system log or so. See below (`Console switching') on how to set them
266 up and switch between them.
270 4
\b4.
\b. R
\bRe
\bes
\bse
\bet
\btt
\bti
\bin
\bng
\bg y
\byo
\bou
\bur
\br t
\bte
\ber
\brm
\bmi
\bin
\bna
\bal
\bl
273 There is garbage on the screen, or all your keystrokes are echoed as
274 line drawing characters. What to do?
276 Many programs will redraw the screen when Ctrl-L is typed. This might
277 help when there is some modem noise or broadcast message on your
278 screen. The command clear will clear the screen.
280 The command reset will reset the console driver. This helps when the
281 screen is full of funny graphic characters, and also if it is reduced
282 to the bottom line. If you don't have this command, or if it does
283 something else, make your own by putting the following two lines in an
284 executable file reset in your PATH:
293 that is, you want to send the two characters ESC c to the console.
295 Why is it that the display sometimes gets confused and gives you a
296 24-line or 1-line screen, instead of the usual 25 lines? Well, the
297 main culprit is the use of TERM=vt100 (or some other entry with 24
298 lines) instead of TERM=linux when logged in remotely. If this happens
299 on /dev/tty2 then typing
309 on some other VT (where 4 symbols are typed to cat: ESC, c, ENTER,
310 Ctrl-D) and refreshing the screen on /dev/tty2 (perhaps using Ctrl-L)
311 will fix things. Of course the permanent fix is to use the right term-
312 cap or terminfo entry.
314 Why is it that you sometimes get a lot of line-drawing characters,
315 e.g., after catting a binary to the screen? Well, there are various
316 character set changing escape sequences, and by accident your binary
317 might contain some of these. The ESC c is a general reset, a cure for
318 all, but if you know precisely what went wrong you can repair it
319 without resetting other console attributes. For example, after
329 your shell prompt will be all line-drawing characters. Now do (typing
338 and all is well again. (Three symbols typed to each cat: Ctrl-N (or
339 Ctrl-O), ENTER, Ctrl-D.) To understand what is happening, see `The
340 console character sets' below.
342 If you loaded some strange font, and want to return to the default,
350 will do (provided you stored the default font in the default place).
351 If this default font does not contain an embedded Unicode map (and
352 gives the wrong symbols for accented characters), then say
368 then I have a German keyboard, and the key left of the Enter key gives
369 me a-umlaut. This works, because the a-umlaut occurs on the CP437 code
370 page and the kernel Unicode map is initialized to CP437, and my video
371 card has a CP437 font built-in. If I now load an ISO 8859-1 font with
379 then everything still works, because setfont invalidates the kernel
380 Unicode map (if there is no Unicode map attached to the font), and
381 without map the kernel goes directly to the font, and that is pre-
382 cisely correct for an ISO 8859-1 system with iso01.f16 font. But
383 going back to the previous font with
391 gives capital Sigma's instead of a-umlaut - all accented letters are
392 mixed up because also this font has no embedded Unicode map. After
397 which loads the default Unicode map (which is right for the default
398 font) all works correctly again. Usually loadunimap is not invoked
399 directly, but via setfont. Thus, the previous two commands may be
408 The Ethiopian fonts and the lat1u*.psf fonts have embedded Unicode
409 code map. Most of the others don't.
411 On old terminals output involving tabs may require a delay, and you
422 You can change the video mode using resizecons or SVGATextMode. This
423 usually settles the output side. On the input side there are many
424 things that might be wrong. If X or DOOM or some other program using
425 raw mode crashed, your keyboard may still be in raw (or mediumraw)
426 mode, and it is difficult to give commands. (See "How to get out of
427 raw mode" below.) If you loaded a bad keymap, then
435 loads the default map again, but it may well be difficult to type `-'!
444 Sometimes even the letters are garbled. It is useful to know that
445 there are four main types of keyboards: QWERTY, QWERTZ, AZERTY and
446 DVORAK. The first three are named after the first six letter keys,
447 and roughly represent the English, German and French speaking coun-
448 tries. Compared to QWERTY, the QWERTZ map interchanges Y and Z. Com-
449 pared to QWERTY, the AZERTY map interchanges Q and A, W and Z, and has
450 its M right of the L, at the semicolon position. DVORAK has an
451 entirely different letter ordering. There are two types of Turkish
452 keyboard. The so-called `Q'-keyboard has a QWERTY layout, while the
453 `F'-keyboard has an entirely different layout, let us say fgGIod,
454 where G stands for Gbreve and I for dotlessi.
457 4
\b4.
\b.1
\b1.
\b. K
\bKe
\bey
\byb
\bbo
\boa
\bar
\brd
\bd h
\bha
\bar
\brd
\bdw
\bwa
\bar
\bre
\be r
\bre
\bes
\bse
\bet
\bt
460 Things may be wrong on a lower level than Linux knows about. There
461 are at least two distinct lower levels (keyboard and keyboard
462 controller) where one can give the command "keyboard disable" to the
463 keyboard hardware. Keyboards can often be programmed to use one out
464 of three different sets of scancodes.
466 However, I do not know of cases where this turned out to be a problem.
468 Some keyboards have a remapping capability built in. Stormy Henderson
469 (stormy@Ghost.Net) writes: `If it's your keyboard accidently being
470 reprogrammed, you can (on a Gateway AnyKey keyboard) press control-
471 alt-suspend_macro to reset the keys to normal.'
474 5
\b5.
\b. D
\bDe
\bel
\ble
\bet
\bte
\be a
\ban
\bnd
\bd B
\bBa
\bac
\bck
\bks
\bsp
\bpa
\bac
\bce
\be
477 Getting Delete and Backspace to work just right is nontrivial,
478 especially in a mixed environment, where you talk to console, to X, to
479 bash, to emacs, login remotely, etc. You may have to edit several
480 configuration files to tell all of the programs involved precisely
481 what you want. On the one hand, there is the matter of which keys
482 generate which codes (and how these codes are remapped by e.g. kermit
483 or emacs), and on the other hand the question of what functions are
486 People often complain `my backspace key does not work', as if this key
487 had a built-in function `delete previous character'. Unfortunately,
488 all this key, or any key, does is producing a code, and one only can
489 hope that the kernel tty driver and all application programs can be
490 configured such that the backspace key indeed does function as a
491 `delete previous character' key.
493 Most Unix programs get their tty input via the kernel tty driver in
494 `cooked' mode, and a simple stty command determines the erase
495 character. However, programs like bash and emacs and X do their own
496 input handling, and have to be convinced one-by-one to do the right
500 5
\b5.
\b.1
\b1.
\b. H
\bHo
\bow
\bw t
\bto
\bo t
\bte
\bel
\bll
\bl U
\bUn
\bni
\bix
\bx w
\bwh
\bha
\bat
\bt c
\bch
\bha
\bar
\bra
\bac
\bct
\bte
\ber
\br y
\byo
\bou
\bu w
\bwa
\ban
\bnt
\bt t
\bto
\bo u
\bus
\bse
\be t
\bto
\bo d
\bde
\bel
\ble
\bet
\bte
\be t
\bth
\bhe
\be
501 l
\bla
\bas
\bst
\bt t
\bty
\byp
\bpe
\bed
\bd c
\bch
\bha
\bar
\bra
\bac
\bct
\bte
\ber
\br
511 If the character is erased, but in a funny way, then something is
512 wrong with your tty settings. If echoprt is set, then erased charac-
513 ters are enclosed between \ and /. If echoe is not set, then the
514 erase char is echoed (which is reasonable when it is a printing char-
515 acter, like #). Most people will want stty echoe -echoprt. Saying
516 stty sane will do this and more. Saying stty -a shows your current
517 settings. How come this is not right by default? It is, if you use
520 Note that many programs (like bash, emacs etc.) have their own
521 keybindings (defined in ~/.inputrc, ~/.emacs etc.) and are unaffected
522 by the setting of the erase character.
524 The standard Unix tty driver does not recognize a cursor, or keys
525 (like the arrow keys) to move the current position, and hence does not
526 have a command `delete current character' either. But for example you
527 can get bash on the console to recognize the Delete key by putting
529 set editing-mode emacs
538 5
\b5.
\b.1
\b1.
\b.1
\b1.
\b. `
\b`G
\bGe
\bet
\btt
\bty
\by u
\bus
\bse
\bed
\bd t
\bto
\bo d
\bdo
\bo t
\bth
\bhe
\be r
\bri
\big
\bgh
\bht
\bt t
\bth
\bhi
\bin
\bng
\bg w
\bwi
\bit
\bth
\bh D
\bDE
\bEL
\bL a
\ban
\bnd
\bd B
\bBS
\bS b
\bbu
\but
\bt i
\bis
\bs b
\bbr
\bro
\bo-
\b-
539 k
\bke
\ben
\bn n
\bno
\bow
\bw?
\b?'
\b'
542 Earlier, the console driver would do BS Space BS (\010\040\010) when
543 it got a DEL (\177). Nowadays, DEL's are ignored (as they should be,
544 since the driver emulates a vt100). Get a better getty, i.e., one that
548 5
\b5.
\b.1
\b1.
\b.2
\b2.
\b. `
\b`L
\bLo
\bog
\bgi
\bin
\bn b
\bbe
\beh
\bha
\bav
\bve
\bes
\bs d
\bdi
\bif
\bff
\bfe
\ber
\bre
\ben
\bnt
\btl
\bly
\by a
\bat
\bt t
\bth
\bhe
\be f
\bfi
\bir
\brs
\bst
\bt a
\ban
\bnd
\bd s
\bse
\bec
\bco
\bon
\bnd
\bd l
\blo
\bog
\bgi
\bin
\bn
549 a
\bat
\btt
\bte
\bem
\bmp
\bpt
\bts
\bs?
\b?'
\b'
552 At the first attempt, you are talking to getty. At the second attempt,
553 you are talking to login, a different program.
556 5
\b5.
\b.2
\b2.
\b. H
\bHo
\bow
\bw t
\bto
\bo t
\bte
\bel
\bll
\bl L
\bLi
\bin
\bnu
\bux
\bx w
\bwh
\bha
\bat
\bt c
\bco
\bod
\bde
\be t
\bto
\bo g
\bge
\ben
\bne
\ber
\bra
\bat
\bte
\be w
\bwh
\bhe
\ben
\bn a
\ba k
\bke
\bey
\by i
\bis
\bs p
\bpr
\bre
\bes
\bss
\bse
\bed
\bd
559 On the console, or, more precisely, when not in (MEDIUM)RAW mode, use
562 % loadkeys mykeys.map
570 % xmodmap mykeys.xmap
575 Note that (since XFree86-2.1) X reads the Linux settings of the
576 keymaps when initialising the X keymap. Although the two systems are
577 not 100% compatible, this should mean that in many cases the use of
578 xmodmap has become superfluous.
580 For example, suppose that you would like the Backspace key to send a
581 BackSpace (Ctrl-H, octal 010) and the grey Delete key a DEL (octal
582 0177). Add the following to /etc/rc.local (or wherever you keep your
583 local boot-time stuff):
586 /usr/bin/loadkeys << EOF
587 keycode 14 = BackSpace
594 Note that this will only change the function of these keys when no
595 modifiers are used. (You need to specify a keymaps line to tell which
596 keymaps should be affected if you want to change bindings on more
597 keymaps.) The Linux kernel default lets Ctrl-Backspace generate
598 BackSpace - this is sometimes useful as emergency escape, when you
599 find you can only generate DELs.
601 The left Alt key is sometimes called the Meta key, and by default the
602 combinations AltL-X are bound to the symbol MetaX. But what character
603 sequence is MetaX? That is determined (per-tty) by the Meta flag, set
604 by the command setmetamode. The two choices are: ESC X or X or-ed with
607 Many distributions have a loadkeys command somewhere in the bootup
608 sequence. For example, one may have the name of the desired keymap in
609 /etc/sysconfig/keyboard and the loadkeys command that loads it in
610 /etc/rc.d/init.d/keytable. Or one may have the actual default keymap
611 in /etc/default.keytab and the loadkeys command that loads it in
612 /etc/rc.d/boot. Etc. Instead of adding a local modification to the
613 default, one can of course change the default by editing the default
614 keymap or changing the name of the keymap to be loaded at boot time.
615 Note that loadkeys itself has default keymap defkeymap.map located
616 somewhere under /usr/lib/kbd or /usr/share/kbd (just like all other
617 keymaps) and this may not yet be available in single user boot before
618 /usr has been mounted.
621 5
\b5.
\b.2
\b2.
\b.1
\b1.
\b. `
\b`W
\bWh
\bhy
\by d
\bdo
\boe
\bes
\bsn
\bn'
\b't
\bt t
\bth
\bhe
\be B
\bBa
\bac
\bck
\bks
\bsp
\bpa
\bac
\bce
\be k
\bke
\bey
\by g
\bge
\ben
\bne
\ber
\bra
\bat
\bte
\be B
\bBa
\bac
\bck
\bkS
\bSp
\bpa
\bac
\bce
\be b
\bby
\by d
\bde
\bef
\bfa
\bau
\bul
\blt
\bt?
\b?'
\b'
624 (i) Because the VT100 had a Delete key above the Enter key.
626 (ii) Because Linus decided so.
629 5
\b5.
\b.3
\b3.
\b. H
\bHo
\bow
\bw t
\bto
\bo t
\bte
\bel
\bll
\bl X
\bX t
\bto
\bo i
\bin
\bnt
\bte
\ber
\brc
\bch
\bha
\ban
\bng
\bge
\be D
\bDe
\bel
\ble
\bet
\bte
\be a
\ban
\bnd
\bd B
\bBa
\bac
\bck
\bks
\bsp
\bpa
\bac
\bce
\be
634 % xmodmap -e "keysym BackSpace = Delete" -e "keysym Delete = BackSpace"
639 Or, if you just want the Backspace key to generate a BackSpace:
642 % xmodmap -e "keycode 22 = BackSpace"
647 Or, if you just want the Delete key to generate a Delete:
650 % xmodmap -e "keycode 107 = Delete"
655 (but usually this is the default binding already).
661 5
\b5.
\b.4
\b4.
\b. H
\bHo
\bow
\bw t
\bto
\bo t
\bte
\bel
\bll
\bl e
\bem
\bma
\bac
\bcs
\bs w
\bwh
\bha
\bat
\bt t
\bto
\bo d
\bdo
\bo w
\bwh
\bhe
\ben
\bn i
\bit
\bt r
\bre
\bec
\bce
\bei
\biv
\bve
\bes
\bs a
\ba D
\bDe
\bel
\ble
\bet
\bte
\be o
\bor
\br
662 B
\bBa
\bac
\bck
\bks
\bsp
\bpa
\bac
\bce
\be
665 Put in your .emacs file lines like
668 (global-set-key "\?" 'help-command)
669 (global-set-key "\C-h" 'delete-backward-char)
674 Of course you can bind other commands to other keys in the same way.
675 Note that various major and minor modes redefine keybindings. For
676 example, in incremental search mode one finds the code
679 (define-key map "\177" 'isearch-delete-char)
680 (define-key map "\C-h" 'isearch-mode-help)
685 This means that it may be a bad idea to use the above two global-set-
686 key commands. There are too many places where there are built-in
687 assumptions about Ctrl-H = help and DEL = delete. That doesn't mean
688 that you have to setup keys so that Backspace generates DEL. But if it
689 doesn't then it is easiest to remap them at the lowest possible level
693 5
\b5.
\b.5
\b5.
\b. H
\bHo
\bow
\bw t
\bto
\bo t
\bte
\bel
\bll
\bl e
\bem
\bma
\bac
\bcs
\bs t
\bto
\bo i
\bin
\bnt
\bte
\ber
\brc
\bch
\bha
\ban
\bng
\bge
\be D
\bDe
\bel
\ble
\bet
\bte
\be a
\ban
\bnd
\bd B
\bBa
\bac
\bck
\bks
\bsp
\bpa
\bac
\bce
\be
696 Put in your .emacs file lines
699 (setq keyboard-translate-table (make-string 128 0))
702 (aset keyboard-translate-table i i)
704 (aset keyboard-translate-table ?\b ?\^?)
705 (aset keyboard-translate-table ?\^? ?\b)
710 Recent versions of emacs have a function keyboard-translate and one
711 may simplify the above to
714 (keyboard-translate ?\C-h ?\C-?)
715 (keyboard-translate ?\C-? ?\C-h)
720 Note that under X emacs can distinguish between Ctrl-h and the
721 Backspace key (regardless of what codes these produce on the console),
722 and by default emacs will view the Backspace key as DEL (and do dele-
723 tion things, as bound to that character, rather than help things,
724 bound to Ctrl-H). One can distinguish Backspace and Delete, e.g. by
727 (global-unset-key [backspace] )
728 (global-set-key [backspace] 'delete-backward-char)
729 (global-unset-key [delete] )
730 (global-set-key [delete] 'delete-char)
736 5
\b5.
\b.6
\b6.
\b. H
\bHo
\bow
\bw t
\bto
\bo t
\bte
\bel
\bll
\bl k
\bke
\ber
\brm
\bmi
\bit
\bt t
\bto
\bo i
\bin
\bnt
\bte
\ber
\brc
\bch
\bha
\ban
\bng
\bge
\be D
\bDe
\bel
\ble
\bet
\bte
\be a
\ban
\bnd
\bd B
\bBa
\bac
\bck
\bks
\bsp
\bpa
\bac
\bce
\be
739 Put in your .kermrc file the lines
749 5
\b5.
\b.7
\b7.
\b. H
\bHo
\bow
\bw t
\bto
\bo t
\bte
\bel
\bll
\bl x
\bxt
\bte
\ber
\brm
\bm t
\bto
\bo i
\bin
\bnt
\bte
\ber
\brc
\bch
\bha
\ban
\bng
\bge
\be D
\bDe
\bel
\ble
\bet
\bte
\be a
\ban
\bnd
\bd B
\bBa
\bac
\bck
\bks
\bsp
\bpa
\bac
\bce
\be
753 XTerm*VT100.Translations: #override\n\
754 <KeyPress> BackSpace : string(0x7f)\n\
755 <KeyPress> Delete : string(0x08)\n
761 5
\b5.
\b.8
\b8.
\b. H
\bHo
\bow
\bw t
\bto
\bo t
\bte
\bel
\bll
\bl x
\bxt
\bte
\ber
\brm
\bm a
\bab
\bbo
\bou
\but
\bt y
\byo
\bou
\bur
\br f
\bfa
\bav
\bvo
\bou
\bur
\bri
\bit
\bte
\be t
\btt
\bty
\by m
\bmo
\bod
\bde
\bes
\bs
764 Normally xterm will inherit the tty modes from its invoker. Under
765 xdm, the default erase and kill characters are # and @, as in good old
766 Unix Version 6. If you don't like that, you might put something like
769 XTerm*ttymodes: erase ^? kill ^U intr ^C quit ^\ eof ^D \
770 susp ^Z start ^Q stop ^S eol ^@
775 in /usr/lib/X11/app-defaults/XTerm or in $HOME/.Xresources, assuming
779 xrdb -merge $HOME/.Xresources
784 in your $HOME/.xinitrc or $HOME/.xsession.
787 5
\b5.
\b.9
\b9.
\b. H
\bHo
\bow
\bw t
\bto
\bo t
\bte
\bel
\bll
\bl x
\bxm
\bmo
\bos
\bsa
\bai
\bic
\bc t
\bth
\bha
\bat
\bt t
\bth
\bhe
\be B
\bBa
\bac
\bck
\bks
\bsp
\bpa
\bac
\bce
\be k
\bke
\bey
\by g
\bge
\ben
\bne
\ber
\bra
\bat
\bte
\bes
\bs a
\ba D
\bDE
\bEL
\bL
793 *XmText.translations: #override\n\
794 <Key>osfDelete: delete-previous-character()
795 *XmTextField.translations: #override\n\
796 <Key>osfDelete: delete-previous-character()
801 in your $HOME/.Xdefaults or $HOME/.Xresources helps. (What file? The
802 file that is fed to xrdb, for example in .xinitrc.)
804 The netscape FAQ, however, says:
806 Why doesn't my Backspace key work in text fields?
807 By default, Linux and XFree86 come with the Backspace and Delete keys
808 misconfigured. All Motif programs (including, of course, Netscape
809 Navigator) will malfunction in the same way.
811 The Motif spec says that Backspace is supposed to delete the previous
812 character and Delete is supposed to delete the following character.
813 Linux and XFree86 come configured with both the Backspace and Delete
814 keys generating Delete.
816 You can fix this by using any one of the xmodmap, xkeycaps, or
817 loadkeys programs to make the key in question generate the BackSpace
818 keysym instead of Delete.
820 You can also fix it by having a .motifbind file; see the man page
821 for VirtualBindings(3).
823 Note: Don't use the *XmText.translations or *XmTextField.translations
824 resources to attempt to fix this problem. If you do, you will blow
825 away Netscape Navigator's other text-field key bindings.
830 5
\b5.
\b.1
\b10
\b0.
\b. A
\bA b
\bbe
\bet
\btt
\bte
\ber
\br s
\bso
\bol
\blu
\but
\bti
\bio
\bon
\bn f
\bfo
\bor
\br M
\bMo
\bot
\bti
\bif
\bf-
\b-u
\bus
\bsi
\bin
\bng
\bg p
\bpr
\bro
\bog
\bgr
\bra
\bam
\bms
\bs,
\b, l
\bli
\bik
\bke
\be n
\bne
\bet
\bts
\bsc
\bca
\bap
\bpe
\be
833 Ted Kandell (ted@tcg.net) suggests the following:
835 Somewhere in your .profile add the following:
843 If you are using bash, add the following lines to your .inputrc:
847 "\C-h": backward-delete-char
852 Add the following lines to your .xinitrc file:
860 keycode 22 = BackSpace osfBackSpace
864 # start your window manager here, for example:
865 #(fvwm) 2>&1 | tee /dev/tty /dev/console
870 keycode 14 = BackSpace
877 This will definitely work for a PC 101 or 102 key keyboard with any
878 Linux/XFree86 layout.
880 The important part to making Motif apps like Netscape work properly is
881 adding osfBackSpace to keycode 22 in addition to BackSpace.
883 Note that there must be spaces on either side of the = sign.
887 5
\b5.
\b.1
\b11
\b1.
\b. W
\bWh
\bha
\bat
\bt a
\bab
\bbo
\bou
\but
\bt t
\bte
\ber
\brm
\bmc
\bca
\bap
\bp a
\ban
\bnd
\bd t
\bte
\ber
\brm
\bmi
\bin
\bnf
\bfo
\bo?
\b?
890 When people have problems with backspace, they tend to look at their
891 termcap (or terminfo) entry for the terminal, and indeed, there does
892 exist a kb (or kbs) capability describing the code generated by the
893 Backspace key. However, not many programs use it, so unless you are
894 having problems with one particular program only, probably the fault
895 is elsewhere. Of course it is a good idea anyway to correct your
896 termcap (terminfo) entry. See also below under "The TERM variable".
899 5
\b5.
\b.1
\b12
\b2.
\b. A
\bA c
\bco
\bom
\bmp
\bpl
\ble
\bet
\bte
\be s
\bso
\bol
\blu
\but
\bti
\bio
\bon
\bn
901 There are many possibilities to get a functioning system. Can't you
902 give one complete set of settings that works?
904 One way of getting a setup that works in all contexts is to have the
905 Backspace key generate DEL when on the console (or xterm), and
906 BackSpace when under X. Maybe that is most convenient - there are too
907 many X utilities that expect BackSpace, and emacs on the console or
908 xterm expects DEL, while emacs under X can distinguish [BackSpace]
909 from Ctrl-H and does the right thing.
911 What is needed? No loadkeys changes, since the Backspace key already
912 generates DEL by default. No stty settings, they are OK by default.
913 No X settings, they are OK by default. One just has to tell xterm
914 that the Backspace key should generate DEL: put
917 XTerm*VT100.Translations: #override\n\
918 <KeyPress> BackSpace : string(0x7f)\n\
925 xrdb -merge .Xresources
930 in .xinitrc, and you are settled.
933 6
\b6.
\b. T
\bTh
\bhe
\be c
\bco
\bon
\bns
\bso
\bol
\ble
\be c
\bch
\bha
\bar
\bra
\bac
\bct
\bte
\ber
\br s
\bse
\bet
\bts
\bs
936 The kernel first tries to figure out what symbol is meant by any given
937 user byte, and next where this symbol is located in the current font.
939 The kernel knows about 5 translations of bytes into console-screen
940 symbols. In Unicode (UTF-8) mode, the UTF-8 code is just converted
941 directly into Unicode. The assumption is that almost all symbols one
942 needs are present in Unicode, and for the cases where this does not
943 hold the codes 0xff** are reserved for direct font access. When not
944 in Unicode mode, one of four translation tables is used. The four
945 tables are: a) Latin1 -> Unicode, b) VT100 graphics -> Unicode, c) PC
946 -> Unicode, d) user-defined.
948 There are two character sets, called G0 and G1, and one of them is the
949 current character set. (Initially G0.) Typing Ctrl-N causes G1 to
950 become current, Ctrl-O causes G0 to become current.
952 These variables G0 and G1 point at a translation table, and can be
953 changed by the user. Initially they point at tables a) and b),
954 respectively. The sequences ESC ( B and ESC ( 0 and ESC ( U and ESC (
955 K cause G0 to point at translation table a), b), c) and d),
956 respectively. The sequences ESC ) B and ESC ) 0 and ESC ) U and ESC )
957 K cause G1 to point at translation table a), b), c) and d),
960 The sequence ESC c causes a terminal reset, which is what you want if
961 the screen is all garbled. The oft-advised echo ^V^O will only make G0
962 current, but there is no guarantee that G0 points at table a). In
963 some distributions there is a program reset(1) that just does echo
964 ^[c. If your termcap entry for the console is correct (and has an
965 entry :rs=\Ec:), then also setterm -reset will work.
967 The user-defined mapping table can be set using mapscrn(8). The
968 result of the mapping is that if a symbol c is printed, the symbol s =
969 map[c] is sent to the video memory. The bitmap that corresponds to s
970 is found in the character ROM, and can be changed using setfont(8).
973 7
\b7.
\b. C
\bCo
\bon
\bns
\bso
\bol
\ble
\be s
\bsw
\bwi
\bit
\btc
\bch
\bhi
\bin
\bng
\bg
976 By default, console switching is done using Alt-Fn or Ctrl-Alt-Fn.
977 Under X (or recent versions of dosemu), only Ctrl-Alt-Fn works. Many
978 keymaps will allow cyclic walks through all allocated consoles using
979 Alt-RightArrow and Alt-LeftArrow.
981 XFree86 1.3 does not know that Alt is down when you switch to the X
982 window. Thus, you cannot switch immediately to some other VT again but
983 have to release Alt first. In the other direction this should work:
984 the kernel always keeps track of the up/down status of all keys. (As
985 far as possible: on some keyboards some keys do not emit a scancode
986 when pressed (e.g.: the PFn keys of a FOCUS 9000) or released (e.g.:
987 the Pause key of many keyboards).)
989 XFree86 1.3 saves the fonts loaded in the character ROMs when started,
990 and restores it on a console switch. Thus, the result of setfont on a
991 VT is wiped out when you go to X and back. Using setfont under X will
992 lead to funny results.
994 One can change VT under program control using the chvt command.
997 7
\b7.
\b.1
\b1.
\b. C
\bCh
\bha
\ban
\bng
\bgi
\bin
\bng
\bg t
\bth
\bhe
\be n
\bnu
\bum
\bmb
\bbe
\ber
\br o
\bof
\bf V
\bVi
\bir
\brt
\btu
\bua
\bal
\bl C
\bCo
\bon
\bns
\bso
\bol
\ble
\bes
\bs
1000 This question still comes up from time to time, but the answer is: you
1001 already have enough of them. Since kernel version 1.1.54, there are
1002 between 1 and 63 virtual consoles. A new one is created as soon as it
1003 is opened. It is removed by the utility deallocvt (but it can be
1004 removed only when no processes are associated to it anymore, and no
1005 text on it has been selected by programs like selection or gpm).
1007 For older kernels, change the line
1010 #define NR_CONSOLES 8
1015 in include/linux/tty.h (don't increase this number beyond 63), and
1016 recompile the kernel.
1018 If they do not exist yet, create the tty devices with MAKEDEV or mknod
1019 ttyN c 4 N where N denotes the tty number. For example,
1022 for i in 9 10 11 12; do mknod /dev/tty$i c 4 $i; done
1027 or, better (since it also takes care of owner and permissions),
1030 for i in 9 10 11 12; do /dev/MAKEDEV tty$i; done
1035 If you want the new VCs to run getty, add lines in /etc/inittab. (But
1036 it is much better to have only two getty's running, and to create more
1037 consoles dynamically as the need arises. That way you'll have more
1038 memory when you don't use all these consoles, and also more consoles,
1039 in case you really need them. Edit /etc/inittab and comment out all
1040 getty's except for the first two.)
1042 When the consoles are allocated dynamically, it is usually easiest to
1043 have only one or two running getty. More are opened by open -l -s
1044 bash. Unused consoles (without associated processes) are deallocated
1045 using deallocvt (formerly disalloc). But, you say, I am involved in
1046 activities when I suddenly need more consoles, and do not have a bash
1047 prompt available to give the open command. Fortunately it is possible
1048 to create a new console upon a single keystroke, regardless of what is
1049 happening at the current console.
1051 If you have spawn_login from kbd-0.96.tar.gz and you put
1058 alt keycode 103 = Spawn_Console
1065 in /etc/rc.local, then typing Alt-UpArrow will create a fresh VC run-
1066 ning login (and switch to it). With spawn_console & instead of
1067 spawn_login & you'll have bash running there. See also open-1.4.tgz
1068 and dynamic-vc-1.1.tar.gz.
1070 What action should be taken upon this Spawn_Console keypress can also
1071 be set in /etc/inittab under kbrequest, if you have a recent init. See
1074 (This action can be something entirely different - I just called the
1075 key Spawn_Console because that is what I used it for. When used for
1076 other purposes it is less confusing to use its synonym KeyboardSignal.
1077 For example, some people like to put the lines
1080 kb::kbrequest:/sbin/shutdown -h now
1085 in /etc/inittab, and
1088 control alt keycode 79 = KeyboardSignal
1089 control alt keycode 107 = KeyboardSignal
1094 in their keymap. Now Ctrl-Alt-End will do a system shutdown.)
1096 You can only login as "root" on terminals listed in /etc/securetty.
1097 There exist programs that read terminal settings from files /etc/ttys
1098 and /etc/ttytype. If you have such files, and create additional
1099 consoles, then it might be a good idea to also add entries for them in
1103 8
\b8.
\b. C
\bCt
\btr
\brl
\bl-
\b-A
\bAl
\blt
\bt-
\b-D
\bDe
\bel
\bl a
\ban
\bnd
\bd o
\bot
\bth
\bhe
\ber
\br s
\bsp
\bpe
\bec
\bci
\bia
\bal
\bl k
\bke
\bey
\by c
\bco
\bom
\bmb
\bbi
\bin
\bna
\bat
\bti
\bio
\bon
\bns
\bs
1107 8
\b8.
\b.1
\b1.
\b. C
\bCt
\btr
\brl
\bl-
\b-A
\bAl
\blt
\bt-
\b-D
\bDe
\bel
\bl (
\b(B
\bBo
\boo
\bot
\bt)
\b)
1110 If you press Ctrl-Alt-Del (or whatever key was assigned the keysym
1111 Boot by loadkeys) then either the machine reboots immediately (without
1112 sync), or init is sent a SIGINT. The former behaviour is the default.
1113 The default can be changed by root, using the system call reboot(),
1114 see ctrlaltdel(8). Some init's change the default. What happens when
1115 init gets SIGINT depends on the version of init used - often it will
1116 be determined by the pf entry in /etc/inittab (which means that you
1117 can run an arbitrary program in this case). In the current kernel
1118 Ctrl-AltGr-Del is no longer by default assigned to Boot.
1123 8
\b8.
\b.2
\b2.
\b. O
\bOt
\bth
\bhe
\ber
\br c
\bco
\bom
\bmb
\bbi
\bin
\bna
\bat
\bti
\bio
\bon
\bns
\bs
1127 Name Default binding
1128 -------------------------------
1129 Show_Memory Shift-Scrollock
1130 Show_Registers AltGr-ScrollLock
1131 Show_State Ctrl-ScrollLock
1132 Console_n Alt-Fn and Ctrl-Alt-Fn (1 <= n <= 12)
1133 Console_{n+12} AltGr-Fn (1 <= n <= 12)
1134 Incr_Console Alt-RightArrow
1135 Decr_Console Alt-LeftArrow
1136 Last_Console Alt[Gr]-PrintScreen
1137 Scroll_Backward Shift-PageUp
1138 Scroll_Forward Shift-PageDown
1139 Caps_On (CapsLock is a toggle; this key sets)
1145 8
\b8.
\b.3
\b3.
\b. X
\bX C
\bCo
\bom
\bmb
\bbi
\bin
\bna
\bat
\bti
\bio
\bon
\bns
\bs
1149 Ctrl-Alt-Fn Switch to VT n
1150 Ctrl-Alt-KP+ Next mode
1151 Ctrl-Alt-KP- Previous mode
1152 Ctrl-Alt-Backspace Kill X
1155 On some motherboards, Ctrl-Alt-KP- and Ctrl-Alt-KP+ will be equivalent
1156 to pressing the Turbo button. That is, both will produce the scancodes
1157 1d 38 4a ca b8 9d and 1d 38 4e ce b8 9d, and both will switch between
1158 Turbo (>= 25MHz) and non-Turbo (8 or 12 MHz). (Often these key combi-
1159 nations only function this way when enabled by jumpers on the mother-
1162 Perry F Nguyen (pfnguyen@netcom22.netcom.com) writes: AMI BIOS has a
1163 feature that locks up the keyboard and flashes the LED's if the Ctrl-
1164 Alt-Backspace combination is pressed while a BIOS password is enabled,
1165 until the CMOS/BIOS password is typed in.
1168 8
\b8.
\b.4
\b4.
\b. D
\bDo
\bos
\bse
\bem
\bmu
\bu C
\bCo
\bom
\bmb
\bbi
\bin
\bna
\bat
\bti
\bio
\bon
\bns
\bs
1172 Ctrl-Alt-Fn Switch to VT n (from version 0.50; earlier Alt-Fn)
1173 Ctrl-Alt-PgDn Kill dosemu (when in RAW keyboard mode)
1174 (and many other combinations - see the dosemu documentation)
1179 8
\b8.
\b.5
\b5.
\b. C
\bCo
\bom
\bmp
\bpo
\bos
\bsi
\bin
\bng
\bg s
\bsy
\bym
\bmb
\bbo
\bol
\bls
\bs
1182 One symbol may be constructed using several keystrokes.
1184 +
\bo LeftAlt-press, followed by a decimal number typed on the keypad,
1185 followed by LeftAlt-release, yields the symbol with code given by
1186 this number. (In Unicode mode this same mechanism, but then with 4
1187 hexadecimal digits, may be used to define a Unicode symbol.)
1189 +
\bo A dead diacritic followed by a symbol, yields that symbol adorned
1190 with that diacritic. If the combination is undefined, both keys are
1191 taken separately. Which keys are dead diacritics is user-settable;
1192 none is by default. Five (since 2.0.25 six) dead diacritics can be
1193 defined (using loadkeys(1)): dead_grave, dead_acute,
1194 dead_circumflex, dead_tilde, dead_diaeresis (and dead_cedilla).
1195 Precisely what this adorning means is also user-settable: dead-
1196 diacritic, symbol is equivalent to Compose + diacritic + symbol.
1198 +
\bo Compose followed by two symbols yields a combination symbol. These
1199 combinations are user-settable. Today there are 68 combinations
1200 defined by default; you can see them by saying "dumpkeys | grep
1203 +
\bo Then there are `Sticky' modifier keys (since 1.3.33). For example,
1204 one can type Ctrl-C as SControl, C and Ctrl-Alt-BackSpace as
1205 SControl, SAlt, BackSpace.
1207 Note that there are at least four such composition mechanisms:
1209 1. The Linux keyboard driver mechanism, used in conjunction with
1212 2. The X mechanism - see X386keybd(1), later XFree86kbd(1). Under
1213 X11R6: edit /usr/X11R6/lib/X11/locale/iso8859-1/Compose.
1215 See also Andrew D. Balsa's comments at
1216 http://wauug.erols.com/~balsa/linux/deadkeys/index.html.
1218 3. The emacs mechanism obtained by loading "iso-insert.el" or calling
1221 4. The vim mechanism: insert a composed symbol by pressing Ctrl-K
1222 followed by two symbols. A list of the possible combinations is
1223 obtained by the command :digraphs.
1225 For X the order of the two symbols is arbitrary: both Compose-,-c
1226 and Compose-c-, yield a c-cedilla; for Linux and emacs only the
1227 former sequence works by default. For X and vim the list of compose
1228 combinations is fixed. Linux and emacs are flexible. The default
1229 lists are somewhat similar, but the details are different.
1232 8
\b8.
\b.6
\b6.
\b. T
\bTh
\bhe
\be S
\bSy
\bys
\bsR
\bRq
\bq k
\bke
\bey
\by
1234 In case your kernel was compiled with CONFIG_MAGIC_SYSRQ enabled (a
1235 feature that is present since Linux 2.1.43) there is a single key
1236 (defined in <linux/keyboard.h>) to which special system functions are
1237 attached, regardless of the current keyboard mode. For the PC
1238 architecture this special key is, naturally, the Alt+SysRq key, and
1239 any of the two Alt keys will work. (Note that if CONFIG_MAGIC_SYSRQ
1240 was not enabled, the default action of this key is to return to the
1243 If you press this key, do not release it, and hit another key, a
1244 corresponding action is performed. The action is performed whether
1245 anybody is logged in or not, is root or not. For the details, see
1246 drivers/char/sysrq.c. Since this feature is meant only for kernel
1247 hackers, that should suffice. Still, let me add a few remarks.
1249 For the key r the keyboard mode is reset to K_XLATE. For the key k a
1250 SAK and console reset is done. For the key b the machine is rebooted
1251 immediately. (See, not something you want to have enabled on a
1252 production machine.) For the key o the power is turned off (when the
1253 machine is capable of that). For the key s an emergency sync is
1254 scheduled. For the key u an emergency read-only remount is scheduled.
1255 For the keys p,t,m various information is shown (namely the same
1256 information also shown for RAlt,RCtrl,RShift+ScrollLock). For the
1257 keys e,i,l all processes get a SIG_TERM or SIG_KILL, respectively; for
1258 l even the init process is killed. Digits set the log level. Anything
1259 else prints a short summary: SysRq: unRaw saK Boot Off Sync Unmount
1260 showPc showTasks showMem loglevel0-8 tErm kIll killalL.
1262 Note: These are very dangerous actions! And they do not use your
1263 keymap - indeed, are meant for emergency cases where the state of your
1264 keymap, or even of the entire kernel, is uncertain. If you use a
1265 dvorak keyboard - bad luck! Most other people will be able to survive:
1266 the dangerous letters A,M,Q,W,Y,Z that are differently placed on
1267 English, French and German keyboards, are not used for actions. (But
1268 if your finger slips and you hit L instead of K - bye bye to your
1272 9
\b9.
\b. H
\bHo
\bow
\bw t
\bto
\bo g
\bge
\bet
\bt o
\bou
\but
\bt o
\bof
\bf r
\bra
\baw
\bw m
\bmo
\bod
\bde
\be
1275 If some program using K_RAW keyboard mode exits without restoring the
1276 keyboard mode to K_XLATE, then it is difficult to do anything - not
1277 even Ctrl-Alt-Del works. However, it is sometimes possible to avoid
1278 hitting the reset button. (And desirable as well: your users may get
1279 angry if you kill their Hack game by rebooting; you might also damage
1280 your file system.) Easy solutions involve logging in from another
1281 terminal or another machine and doing kbd_mode -a. The procedure
1282 below assumes that no X is running, that the display is in text mode,
1283 and that you are at your bash prompt, that you are using a US keyboard
1284 layout, and that your interrupt character is Ctrl-C.
1286 Step 1. Start X. As follows: press 2 (and don't release), press F12
1287 (and don't release) and immediately afterwards press = . This starts
1288 X. (Explanation: if a key press produces keycode K, then the key
1289 release produces keycode K+128. Probably your shell does not like
1290 these high characters, so we avoid generating them by not releasing
1291 any key. However, we have to be quick, otherwise key repeat starts.
1292 The digit 2 produces a Ctrl-C that discards previous junk, the F12
1293 produces an X and the = a Return.) Probably your screen will be grey
1294 now, since no .xinitrc was specified. However, Ctrl-Alt-Fn will work
1295 and you can go to another VT. (Ctrl-Alt-Backspace also works, but
1296 that exits X, and gets you back into the previous state, which is not
1299 Step 2. Setup to change the keyboard mode. (For example, by sleep 5;
1302 Step 3. Leave X again. Alt-Fx (often Alt-F7) brings you back to X,
1303 and then Ctrl-Alt-Backspace exits X. Within 5 seconds your keyboard
1304 will be usable again.
1306 If you want to prepare for the occasion, then make \215A\301 (3
1307 symbols) an alias for kbd_mode -a. Now just hitting = F7 = (3
1308 symbols) will return you to sanity.
1311 1
\b10
\b0.
\b. T
\bTh
\bhe
\be k
\bke
\bey
\byb
\bbo
\boa
\bar
\brd
\bd L
\bLE
\bED
\bDs
\bs
1314 1. There are per-tty keyboard flags: each VC has its own NumLock,
1315 CapsLock, ScrollLock. By default these keyboard flags are shown in
1316 the LEDs. The usual way to change them is by pressing the
1317 corresponding key. (Side remark: pressing the NumLock key when in
1318 application key mode will not change the NumLock status, but produce
1319 an escape sequence. If you want the NumLock key to always change the
1320 Numlock status, bind it to Bare_Num_Lock.)
1321 2. Next, there are per-tty default keyboard flags, to initialize the
1322 keyboard flags when a reset occurs. Thus if you want NumLock on all
1323 the time, that is possible. The usual way to change them is by
1326 3. There is the possibility that the leds do not reflect the keyboard
1327 flags, but something else.
1329 3A. This something else can be three bits somewhere in the kernel -
1330 which can be used if you want to monitor some hardware or software
1331 status bit(s). If you want this, edit the kernel source to call
1332 register_leds() somewhere.
1334 3B. This something else can also be whatever some user program wants
1335 to show in the LEDs. Thus, people who like such things can make nice
1336 patterns of lights. If you want this, use the KDSETLED ioctl.
1338 This latter use is not per-tty, but the choice between former and
1339 latter use is per-tty.
1341 Summarizing: Each tty has a flag kbd->ledmode. If this has the value
1342 LED_SHOW_FLAGS then the keyboard flags (NumLock etc.) of that tty are
1343 shown. If this has the value LED_SHOW_MEM then three selected memory
1344 addresses are shown. If this has the value LED_SHOW_IOCTL then the
1345 leds show whatever value was last assigned to them using the KDSETLED
1348 One may add that X uses ioctl's to set the LEDs, but fails to reset
1349 its VT when it exits, so after using X there may be one VT that is not
1350 in the default LED_SHOW_FLAGS state. This can be fixed by doing
1351 `setleds -L' on that VT. See setleds(1).
1354 1
\b11
\b1.
\b. T
\bTh
\bhe
\be T
\bTE
\bER
\bRM
\bM v
\bva
\bar
\bri
\bia
\bab
\bbl
\ble
\be
1357 Many programs use the TERM variable and the database /etc/termcap or
1358 /usr/lib/terminfo/* to decide which strings to send for clear screen,
1359 move cursor, etc., and sometimes also to decide which string is sent
1360 by the users backspace key, function keys etc. This value is first
1361 set by the kernel (for the console). Usually, this variable is re-set
1362 by getty, using /etc/ttytype or the argument specified in
1363 /etc/inittab. Sometimes, it is also set in /etc/profile.
1365 Older systems use TERM=console or TERM=con80x25. Newer systems (with
1366 ncurses 1.8.6) use the more specific TERM=linux or TERM=linux-80x25.
1367 However, old versions of setterm test for TERM=con* and hence fail to
1368 work with TERM=linux.
1370 Since kernel version 1.3.2, the kernel default for the console is
1373 If you have a termcap without entry for linux, add the word linux to
1374 the entry for the console:
1377 console|con80x25|linux:\
1382 and make /usr/lib/terminfo/l/linux a copy of or symbolic link to
1383 /usr/lib/terminfo/c/console.
1387 1
\b11
\b1.
\b.1
\b1.
\b. T
\bTe
\ber
\brm
\bmi
\bin
\bnf
\bfo
\bo
1390 The terminfo entry for the linux console from ncurses 1.8.6 misses the
1391 entry kich1=\E[2~, needed by some programs. Edit the file and tic it.
1394 1
\b12
\b2.
\b. H
\bHo
\bow
\bw t
\bto
\bo m
\bma
\bak
\bke
\be o
\bot
\bth
\bhe
\ber
\br p
\bpr
\bro
\bog
\bgr
\bra
\bam
\bms
\bs w
\bwo
\bor
\brk
\bk w
\bwi
\bit
\bth
\bh n
\bno
\bon
\bn-
\b-A
\bAS
\bSC
\bCI
\bII
\bI c
\bch
\bha
\bar
\brs
\bs
1397 In the bad old days this used to be quite a hassle. Every separate
1398 program had to be convinced individually to leave your bits alone.
1399 Not that all is easy now, but recently a lot of gnu utilities have
1400 learned to react to LC_CTYPE=iso_8859_1 or LC_CTYPE=iso-8859-1. Try
1401 this first, and if it doesn't help look at the hints below. Note that
1402 in recent versions of libc the routine setlocale() only works if you
1403 have installed the locale files (e.g. in /usr/lib/locale).
1405 First of all, the 8-th bit should survive the kernel input processing,
1406 so make sure to have stty cs8 -istrip -parenb set.
1408 A. For emacs the details strongly depend on the version. The
1409 information below is for version 19.34. Put lines
1412 (set-input-mode nil nil 1)
1413 (standard-display-european t)
1414 (require 'iso-syntax)
1419 into your $HOME/.emacs. The first line (to be precise: the final 1)
1420 tells emacs not to discard the 8-th bit from input characters. The
1421 second line tells emacs not to display non-ASCII characters as octal
1422 escapes. The third line specifies the syntactic properties and case
1423 conversion table for the Latin-1 character set These last two lines
1424 are superfluous if you have something like LC_CTYPE=ISO-8859-1 in your
1425 environment. (The variable may also be LC_ALL or even LANG. The
1426 value may be anything with a substring `88591' or `8859-1' or
1429 This is a good start. On a terminal that cannot display non-ASCII ISO
1430 8859-1 symbols, the command
1433 (load-library "iso-ascii")
1438 will cause accented characters to be displayed comme {,c}a. If your
1439 keymap does not make it easy to produce non-ASCII characters, then
1442 (load-library "iso-transl")
1447 will make the 2-character sequence Ctrl-X 8 a compose character, so
1448 that the 4-character sequence Ctrl-X 8 , c produces c-cedilla. Very
1458 will toggle ISO-8859-1 accent mode, in which the six characters ', `,
1459 ", ^, ~, / are dead keys modifying the following symbol. Special com-
1460 binations: ~c gives a c with cedilla, ~d gives an Icelandic eth, ~t
1461 gives an Icelandic thorn, "s gives German sharp s, /a gives a with
1462 ring, /e gives an a-e ligature, ~< and ~> give guillemots, ~! gives an
1463 inverted exclamation mark, ~? gives an inverted question mark, and ''
1464 gives an acute accent. This is the default mapping of accents. The
1465 variable iso-languages is a list of pairs (language name, accent map-
1466 ping), and a non-default mapping can be selected using
1469 (iso-accents-customize LANGUAGE)
1474 Here LANGUAGE can be one of "portuguese", "irish", "french",
1475 "latin-2", "latin-1".
1477 Since the Linux default compose character is Ctrl-. it might be
1478 convenient to use that everywhere. Try
1481 (load-library "iso-insert.el")
1482 (define-key global-map [?\C-.] 8859-1-map)
1487 The latter line will not work under xterm, if you use emacs -nw, but
1488 in that case you can put
1491 XTerm*VT100.Translations: #override\n\
1492 Ctrl <KeyPress> . : string("\0308")
1497 in your .Xresources.)
1499 B. For less, put LESSCHARSET=latin1 in the environment. This is also
1500 what you need if you see \255 or <AD> in man output: some versions of
1501 less will render the soft hyphen (octal 0255, hex 0xAD) this way when
1502 not given permission to output Latin-1.
1504 C. For ls, give the option -N. (Probably you want to make an alias.)
1506 D. For bash (version 1.13.*), put
1510 set convert-meta off
1516 into your $HOME/.inputrc.
1523 setenv LC_CTYPE iso_8859_1
1528 If you have nls on your system, then the corresponding routines are
1529 used. Otherwise tcsh will assume iso_8859_1, regardless of the values
1530 given to LANG and LC_CTYPE. See the section NATIVE LANGUAGE SYSTEM in
1531 tcsh(1). (The Danish HOWTO says: setenv LC_CTYPE ISO-8859-1; stty
1534 F. For flex, give the option -8 if the parser it generates must be
1535 able to handle 8-bit input. (Of course it must.)
1537 G. For elm, set displaycharset to ISO-8859-1. (Danish HOWTO: LANG=C
1538 and LC_CTYPE=ISO-8859-1)
1540 H. For programs using curses (such as lynx) David Sibley reports: The
1541 regular curses package uses the high-order bit for reverse video mode
1542 (see flag _STANDOUT defined in /usr/include/curses.h). However,
1543 ncurses seems to be 8-bit clean and does display iso-latin-8859-1
1546 I. For programs using groff (such as man), make sure to use -Tlatin1
1547 instead of -Tascii. Old versions of the program man also use col, and
1548 the next point also applies.
1550 J. For col, make sure 1) that it is fixed so as to do
1551 setlocale(LC_CTYPE,""); and 2) put LC_CTYPE=ISO-8859-1 in the
1554 K. For rlogin, use option -8.
1557 sunsite.unc.edu:/pub/Linux/apps/editors/joe-1.0.8-linux.tar.gz is said
1558 to work after editing the configuration file. Someone else said: joe:
1559 Put the -asis option in /isr/lib/joerc in the first column.
1561 M. For LaTeX: \documentstyle[isolatin]{article}. For LaTeX2e:
1562 \documentclass{article}\usepackage{isolatin} where isolatin.sty is
1563 available from ftp.vlsivie.tuwien.ac.at/pub/8bit.
1565 A nice discussion on the topic of ISO-8859-1 and how to manage 8-bit
1566 characters is contained in the file grasp.insa-
1567 lyon.fr:/pub/faq/fr/accents (in French). Another fine discussion (in
1568 English) can be found in rtfm.mit.edu:pub/usenet-by-
1569 group/comp.answers/internationalization/iso-8859-1-charset.
1571 If you need to fix a program that behaves badly with 8-bit characters,
1572 one thing to keep in mind is that if you have a signed char type then
1573 characters may be negative, and using them as an array index will
1574 fail. Several programs can be fixed by judiciously adding (unsigned
1581 This FAQ/HOWTO is about the Linux keyboard and console, not about X,
1582 which substitutes its own handling. However, it seems useful to
1583 document some of the Linux keyboard and console related properties of
1585 First of all, when X is started (say using startx or xinit) it opens
1586 the first unused console, unless the desired console has been
1587 indicated explicitly, as in xinit -- vt12. Note that this will fail
1588 when there is no device file /dev/tty12, but that it will not fail
1589 when the indicated console was in use already. When X finishes, it
1590 will return to the original console. While it is running one can use
1591 Ctrl-Alt-Fn to switch to VTn.
1593 The XFree86 keymap mechanism is much poorer than the Linux mechanism.
1594 For each keycode there are at most 4 symbols defined, namely for the 4
1595 keymaps plain, shift, mod, mod+shift. What is the modifier mod? It is
1596 the one designated by the symbol Mode_switch. For example, the
1597 command xmodmap keys.dk, where the file keys.dk contains
1600 keycode 64 = Mode_switch
1601 keycode 113 = Mode_switch
1602 keycode 38 = a A aring Aring
1603 keycode 26 = e E ae AE
1604 keycode 32 = o O oslash Ooblique
1609 will make both Alt keys into mod keys, so that Alt+a gives (a-ring),
1610 etc. (Note the illogical naming of oslash and Ooblique.) Such an
1611 xmodmap command can be placed in the .xinitrc shell script that is
1612 executed by default when X is started.
1615 1
\b13
\b3.
\b.1
\b1.
\b. W
\bWh
\bha
\bat
\bt p
\bpr
\bre
\bec
\bci
\bis
\bse
\bel
\bly
\by d
\bdo
\boe
\bes
\bs X
\bXF
\bFr
\bre
\bee
\be8
\b86
\b6-
\b-2
\b2.
\b.1
\b1 d
\bdo
\bo w
\bwh
\bhe
\ben
\bn i
\bit
\bt i
\bin
\bni
\bit
\bti
\bia
\bal
\bli
\biz
\bze
\bes
\bs i
\bit
\bts
\bs
1616 k
\bke
\bey
\bym
\bma
\bap
\bp?
\b?
1619 Since version 2.1, XFree86 will initialize its keymap from the Linux
1620 keymap, as far as possible. However, Linux had 16 entries per key (one
1621 for each combination of the Shift, AltGr, Ctrl, Alt modifiers) and
1622 presently has 256 entries per key, while X has 4 entries per key (one
1623 for each combination of Shift, Mod), so some information is
1626 First X reads the Xconfig file, where definitions of the LeftAlt,
1627 RightAlt, RightCtl, ScrollLock keys as Meta, ModeShift, Compose,
1628 ModeLock or ScrollLock might be found - see X386keybd(1), later
1631 For Mod the LeftAlt key is taken, unless RightCtl was defined as
1632 ModeShift or ModeLock, in which case RightCtl is taken, or RightAlt
1633 was so defined, in which case RightAlt is taken. This determines how
1634 the 4 XFree86 meanings of a key are selected from the 16 Linux
1635 meanings. Note that Linux today does not distinguish by default
1636 between the two Ctrl keys or between the two Shift keys. X does
1639 Now the kernel keymap is read and the usually obvious corresponding X
1640 bindings are made. The bindings for the "action keys" Show_Memory,
1641 Show_State, Show_Registers, Last_Console, Console_n, Scroll_Backward,
1642 Scroll_Forward, Caps_On and Boot are ignored, as are the dead
1643 diacriticals, and the locks (except for ShiftLock), and the "ASCII-x"
1646 Next, the definitions in the Xconfig file are used. (Thus, a
1647 definition of Compose in Xconfig will override its value as found in
1651 What happens to the strings associated with the function keys?
1652 Nothing, X does not have such a concept. (But it is possible to define
1653 strings for function keys in xterm - note however that the window
1654 manager gets the keys first.)
1656 I don't know how to convince xterm that it should use the X keymap
1657 when Alt is pressed; it seems just to look at its resource
1658 eightBitInput, and depending on whether that is true or false either
1659 set the high order bit of the character, or generate an additional
1660 Escape character (just like setmetamode(1) does for the console).
1663 1
\b14
\b4.
\b. U
\bUn
\bnu
\bus
\bsu
\bua
\bal
\bl k
\bke
\bey
\bys
\bs a
\ban
\bnd
\bd k
\bke
\bey
\byb
\bbo
\boa
\bar
\brd
\bds
\bs
1666 The two keys PrintScrn/SysRq and Pause/Break are special in that they
1667 have two keycodes: the former has keycode 84 when Alt is pressed
1668 simultaneously, and keycode 99 otherwise; the latter has keycode 101
1669 when Ctrl is pressed simultaneously, and keycode 119 otherwise.
1670 (Thus, it makes no sense to bind functions to Alt keycode 99 or Ctrl
1673 If you have strange keys, that do not generate any code under Linux
1674 (or generate messages like "unrecognized scancode"), and your kernel
1675 is 1.1.63 or later, then you can use setkeycodes(1) to tell the kernel
1676 about them. They won't work under X, however. Once they have gotten a
1677 keycode from setkeycodes, they can be assigned a function by loadkeys.
1680 1
\b15
\b5.
\b. E
\bEx
\bxa
\bam
\bmp
\bpl
\ble
\bes
\bs o
\bof
\bf u
\bus
\bse
\be o
\bof
\bf l
\blo
\boa
\bad
\bdk
\bke
\bey
\bys
\bs a
\ban
\bnd
\bd x
\bxm
\bmo
\bod
\bdm
\bma
\bap
\bp
1683 Switching Caps Lock and Control on the keyboard (assuming you use
1684 keymaps 0-15; check with dumpkeys | head -1)
1689 keycode 58 = Control
1690 keycode 29 = Caps_Lock
1696 Switching them under X only:
1699 % xmodmap .xmodmaprc
1704 where .xmodmaprc contains lines
1707 remove Lock = Caps_Lock
1708 remove Control = Control_L
1709 keysym Control_L = Caps_Lock
1710 keysym Caps_Lock = Control_L
1711 add Lock = Caps_Lock
1712 add Control = Control_L
1717 What is this about the key numbering? Backspace is 14 under Linux, 22
1718 under X? Well, the numbering can best be regarded as arbitrary; the
1719 Linux number of a key can be found using showkey(1), and the X number
1720 using xev(1). Often the X number will be 8 more than the Linux number.
1722 Something else people like to change are the bindings of the function
1723 keys. Suppose that you want to make F12 produce the string "emacs ".
1729 string F12 = "emacs "
1735 will do this. More explicitly, the procedure is like this: (i) find
1736 the keycodes of the keys to be remapped, using showkey(1). (ii) save
1737 the current keymap, make a copy and edit that:
1740 % dumpkeys > my_keymap
1741 % cp my_keymap trial_keymap
1742 % emacs trial_keymap
1743 % loadkeys trial_keymap
1749 The format of the table can be guessed by looking at the output of
1750 dumpkeys, and is documented in keymaps(5). When the new keymap func-
1751 tions as desired, you can put an invocation
1754 loadkeys my_new_keymap
1759 in /etc/rc.local or so, to execute it automatically at boot-up. Note
1760 that changing modifier keys is tricky, and a newbie can easily get
1761 into a situation only an expert can get out of.
1763 The default directory for keymaps is /usr/lib/kbd/keymaps. The
1764 default extension for keymaps is .map. For example, loadkeys uk would
1765 probably load /usr/lib/kbd/keymaps/i386/qwerty/uk.map. (With kbd-0.95
1766 and older this would be /usr/lib/kbd/keytables and
1767 /usr/lib/kbd/keytables/uk.map.)
1770 (On my machine) /dev/console is a symbolic link to /dev/tty0, and the
1771 kernel regards /dev/tty0 as a synonym for the current VT. XFree86 1.3
1772 changes the owner of /dev/tty0, but does not reset this after
1773 finishing. Thus, loadkeys or dumpkeys might fail because someone else
1774 owns /dev/tty0; in such a case you might run X first. Note that you
1775 cannot change keyboard mappings when not at the console (and not
1779 1
\b15
\b5.
\b.1
\b1.
\b. `
\b`I
\bI c
\bca
\ban
\bn u
\bus
\bse
\be o
\bon
\bnl
\bly
\by o
\bon
\bne
\be f
\bfi
\bin
\bng
\bge
\ber
\br t
\bto
\bo t
\bty
\byp
\bpe
\be w
\bwi
\bit
\bth
\bh'
\b'
1783 "Can the Shift, Ctrl and Alt keys be made to behave as toggles?"
1790 keycode 29 = Control_Lock
1791 keycode 42 = Shift_Lock
1792 keycode 56 = Alt_Lock
1798 the left Control, Shift and Alt keys will act as toggles. The numbers
1799 involved are revealed by showkey (and usually are 29, 97, 42, 54, 56,
1800 100 for left and right control, shift and alt, respectively), and the
1801 functions are Control_Lock, Shift_Lock, Alt_Lock, ALtGr_Lock.
1803 "What about `sticky' modifier keys?"
1805 Since version 1.3.33, the kernel knows about `sticky' modifier keys.
1806 These act on the next key pressed. So, where one earlier needed the
1807 3-symbol sequence Shift_Lock a Shift_Lock to type `A', one can now use
1808 the 2-symbol sequence SShift_Lock a. Versions of the kbd package
1809 older than 0.93 do not yet include code for these sticky modifiers,
1810 and have to invoke them using their hexadecimal codes. For example,
1817 keycode 100 = 0x0c03
1823 will make the right Shift, Ctrl, Alt sticky versions of the left ones.
1824 From 0.93 on you can say
1837 to obtain the same result. This will allow you to type Ctrl-Alt-Del
1838 in three keystrokes with one hand.
1840 The keymaps line in these examples should cover all keymaps you have
1841 in use. You find what keymaps you have in use by
1844 % dumpkeys | head -1
1849 1
\b16
\b6.
\b. C
\bCh
\bha
\ban
\bng
\bgi
\bin
\bng
\bg t
\bth
\bhe
\be v
\bvi
\bid
\bde
\beo
\bo m
\bmo
\bod
\bde
\be
1852 As far as I know there are 6 ways to change resolution:
1854 1. At compile time: change the line
1857 SVGA_MODE= -DSVGA_MODE=NORMAL_VGA
1862 in /usr/src/linux/Makefile.
1864 1A. After compilation: use rdev -v - a terrible hack, but it exists.
1866 2. At boot time: put vga=ask in the lilo config file, and lilo will
1867 ask you what video mode you want. Once you know, put vga=mypreference.
1869 3. At run time: A. Use the resizecons command. (This is a very
1870 primitive wrapper around the VT_RESIZE ioctl.) B. Use the
1871 SVGATextMode command. (This is a less primitive wrapper around the
1874 4. Not "on the console": Under dosemu, or with svgalib etc. you can
1875 change the hardware video mode without the console driver being aware
1876 of it. Sometimes this is useful in getting resizecons or SVGATextMode
1877 set up: use dosemu and some DOS program to get into the desired
1878 videomode, dump (say from another VT) the contents of all video
1879 hardware registers, and use that in the initialization that resizecons
1880 and SVGATextMode require. In some cases where the video mode has
1881 gotten into some unusable state, starting dosemu, relying on the BIOS
1882 to set up the video mode, and then killing dosemu (with kill -9), is
1883 the easiest way to get into shape again.
1886 1
\b16
\b6.
\b.1
\b1.
\b. I
\bIn
\bns
\bst
\btr
\bru
\buc
\bct
\bti
\bio
\bon
\bns
\bs f
\bfo
\bor
\br t
\bth
\bhe
\be u
\bus
\bse
\be o
\bof
\bf r
\bre
\bes
\bsi
\biz
\bze
\bec
\bco
\bon
\bns
\bs
1889 Get svgalib and compile the program restoretextmode. Boot up your
1890 machine in all possible video modes (using vga=ask in the lilo config
1891 file), and write the video hardware register contents to files CxR
1892 (C=cols, R=rows), e.g., 80x25, 132x44, etc. Put these files in
1893 /usr/lib/kbd/videomodes. Now resizecons 132x44 will change videomode
1894 for you (and send SIGWINCH to all processes that need to know about
1895 this, and load another font if necessary).
1897 At present, resizecons only succeeds when there is memory enough for
1898 both the old and the new consoles at the same time.
1901 1
\b17
\b7.
\b. C
\bCh
\bha
\ban
\bng
\bgi
\bin
\bng
\bg t
\bth
\bhe
\be k
\bke
\bey
\byb
\bbo
\boa
\bar
\brd
\bd r
\bre
\bep
\bpe
\bea
\bat
\bt r
\bra
\bat
\bte
\be
1904 At startup, the Linux kernel sets the repeat rate to its maximal
1905 value. For most keyboards this is reasonable, but for some it means
1906 that you can hardly touch a key without getting three copies of the
1907 corresponding symbol. Use the program kbdrate(8) to change the repeat
1908 rate, or, if that doesn't help, edit or remove the section
1915 ______________________________________________________________________
1916 ! set the keyboard repeat rate to the max
1919 xor bx,bx ! clear bx
1921 ______________________________________________________________________
1924 of /usr/src/linux/[arch/i386/]boot/setup.S.
1926 Scott Johnston (sj@zule.com) reports: `To program the repeat rate of a
1927 Gateway AnyKey keyboard all one has to do is press the "Repeat Rate"
1928 key, then a function key F1-F8, then "Repeat Rate" again. F1 is the
1929 slowest possible repeat rate, and F8 is really fast. If you somehow
1930 manage to mess up your AnyKey keyboard doing this, simply press Ctrl-
1931 Alt-SuspndMacro to reset your keyboard to factory default settings.'
1934 1
\b18
\b8.
\b. S
\bSc
\bcr
\bro
\bol
\bll
\bli
\bin
\bng
\bg
1937 There are two ways to get a screen to scroll. The first, called `hard
1938 scrolling', is to leave the text in video memory as it is, but change
1939 the viewing origin. This is very fast. The second, called `soft
1940 scrolling', involves moving all screen text up or down. This is much
1941 slower. The kernel console driver will write text starting at the top
1942 of the video memory, continuing to the bottom, then copy the bottom
1943 part to the top again, and continue, all the time using hard scrolling
1944 to show the right part on the screen. You can scroll back until the
1945 top op the video memory by using Shift-PageUp (the grey PageUp) and
1946 scroll down again using Shift-PageDown (the grey PageDown), assuming a
1947 default keymap. The amount of scrollback is thus limited to the
1948 amount of video memory you happen to have and you cannot increase this
1949 amount. If you need more scrollback, use some program that buffers
1950 the text, like less or screen - by using a buffer on disk you can go
1951 back to what you did last week. (One can set the amount of scrollback
1952 for xterm by adding a line like XTerm*saveLines: 2500 in .Xresources.)
1954 Upon changing virtual consoles, the screen content of the old VT is
1955 copied to kernel memory, and the screen content of the new VT is
1956 copied from kernel memory to video memory. Only the visible screen is
1957 copied, not all of video memory, so switching consoles means losing
1958 the scrollback information.
1960 Sometimes, hard scrolling is undesirable, for example when the
1961 hardware does not have the possibility to change viewing origin. The
1962 first example was a Braille machine that would render the top of video
1963 memory in Braille. There is a kernel boot-time option no-scroll to
1964 tell the console driver not to use hard scrolling. See bootparam(7).
1967 1
\b19
\b9.
\b. S
\bSc
\bcr
\bre
\bee
\ben
\bns
\bsa
\bav
\bvi
\bin
\bng
\bg
1970 setterm -blank _
\bn_
\bn will tell the console driver to blank the screen
1971 after _
\bn_
\bn minutes of inactivity. (With _
\bn_
\bn = 0, screensaving is turned
1972 off. In some old kernels this first took effect after the next
1973 keyboard interrupt.)
1975 The s option of xset(1) will set the X screensaving parameters: xset s
1976 off turns off the screensaver, xset s 10 blanks the screen after 10
1979 The video hardware powersaving modes can be enabled/disabled using the
1980 setvesablank program given in the starting comment of
1981 /usr/src/linux/drivers/char/vesa_blank.c.
1984 2
\b20
\b0.
\b. S
\bSc
\bcr
\bre
\bee
\ben
\bn d
\bdu
\bum
\bmp
\bps
\bs
1987 setterm -dump _
\bN will dump the contents of the screen of /dev/tty_
\bN to a
1988 file screen.dump in the current directory. See setterm(1).
1990 The current contents of the screen of /dev/tty_
\bN can be accessed using
1991 the device /dev/vcs_
\bN (where `vcs' stands for `virtual console
1992 screen'). For example, you could have a clock program that displays
1993 the current time in the upper right hand corner of the console screen
1994 (see the program vcstime in kbd-0.96.tar.gz). Just dumping the
1995 contents goes with cat /dev/vcs_
\bN. These device files /dev/vcs_
\bN do not
1996 contain newlines, and do not contain attributes, like colors. From a
1997 program it is usually better to use /dev/vcsa_
\bN (`virtual console
1998 screen with attributes') instead - it starts with a header giving the
1999 number of rows and columns and the location of the cursor. See
2003 2
\b21
\b1.
\b. S
\bSo
\bom
\bme
\be p
\bpr
\bro
\bop
\bpe
\ber
\brt
\bti
\bie
\bes
\bs o
\bof
\bf t
\bth
\bhe
\be V
\bVT
\bT1
\b10
\b00
\b0 -
\b- a
\bap
\bpp
\bpl
\bli
\bic
\bca
\bat
\bti
\bio
\bon
\bn k
\bke
\bey
\by m
\bmo
\bod
\bde
\be
2006 : Sometimes my cursor keys or keypad keys produce strange codes?
2008 When the terminal is in application cursor key mode the cursor keys
2009 produce Esc O x and otherwise Esc [ x where x is one of A,B,C,D.
2010 Certain programs put the terminal in application cursor key mode; if
2011 you kill them with kill -9, or if they crash, then the mode will not
2017 resets all properties of the current VC. Just changing the cursor
2018 application key mode is done by
2020 % echo -e '\033[?1h'
2025 % echo -e '\033[?1l'
2030 When the terminal is in application keypad key mode the keypad keys
2031 produce Esc O y and otherwise Esc [ z ~ for certain y and z.
2032 Setting application keypad key mode is done by
2047 2
\b22
\b2.
\b. H
\bHa
\bar
\brd
\bdw
\bwa
\bar
\bre
\be i
\bin
\bnc
\bco
\bom
\bmp
\bpa
\bat
\bti
\bib
\bbi
\bil
\bli
\bit
\bty
\by
2050 Several people have noticed that they lose typed characters when a
2051 floppy disk is active. It seems that this might be a problem with
2052 Uni-486WB motherboards.
2054 Tjalling Tjalkens (tjalling@ei.ele.tue.nl) reports very similar
2055 problems with "a no-brand GMB-486 UNP Vesa motherboard with AMD
2056 486DX2-66 CPU" - during floppy activity some keystrokes are lost,
2057 during floppy tape streamer (Conner C 250 MQ) activity many keystrokes
2060 Some people experience sporadic lockups - sometimes associated to hard
2061 disk activity or other I/O.
2063 Ulf Tietz (ulf@rio70.bln.sni.de) wrote: `I have had the same problems,
2064 when I had my motherboard tuned too fast. So I reset all the timings
2065 ( CLK, wait statements etc ) to more conventional values, and the
2068 Bill Hogan (bhogan@crl.com) wrote: `If you have an AMI BIOS, you might
2069 try setting the Gate A20 emulation parameter to "chipset" (if you have
2070 that option). Whenever I have had that parameter set to any of the
2071 other options on my machine ("fast", "both", "disabled") I have had
2072 frequent keyboard lockups.'
2074 There may be a relation between keyboard problems and the video card
2077 Shawn K. Quinn (skquinn@wt.net) wrote: `I have a Zeos Pantera
2078 Pentium-90 that originally came with a Diamond Stealth 64 S3-based
2079 video card. Under X I frequently got q's inserted into my text (how
2080 annoying) especially if I typed very fast (during Netrek for instance,
2081 even more annoying because guess what that does :-( ). Switching to a
2082 Creative Labs Graphics Blaster MA202 solved the problem. I'm assuming
2083 the Stealth 64 did something funny with the timings.'
2086 2
\b23
\b3.
\b. C
\bCo
\bop
\bpy
\byr
\bri
\big
\bgh
\bht
\bt
2088 Copyright (c) 1993-1999 by Andries Brouwer. This document may be
2089 distributed under the terms set forth in the LDP license at
2090 http://sunsite.unc.edu/LDP/COPYRIGHT.html or
2091 ftp://www.win.tue.nl/pub/linux/LDP/COPYRIGHT.txt.
2093 Additions and corrections are welcome. Andries Brouwer - aeb@cwi.nl