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1 '\" t
2 .\" Copyright (c) 1996 Andries Brouwer <aeb@cwi.nl>, Mon Oct 31 22:13:04 1996
3 .\"
4 .\" %%%LICENSE_START(GPLv2+_DOC_ONEPARA)
5 .\" This is free documentation; you can redistribute it and/or
6 .\" modify it under the terms of the GNU General Public License as
7 .\" published by the Free Software Foundation; either version 2 of
8 .\" the License, or (at your option) any later version.
9 .\" %%%LICENSE_END
10 .\"
11 .\" This is combined from many sources.
12 .\" For Linux, the definitive source is of course console.c.
13 .\" About vt100-like escape sequences in general there are
14 .\" the ISO 6429 and ISO 2022 norms, the descriptions of
15 .\" an actual vt100, and the xterm docs (ctlseqs.ms).
16 .\" Substantial portions of this text are derived from a write-up
17 .\" by Eric S. Raymond <esr@thyrsus.com>.
18 .\"
19 .\" Tiny correction, aeb, 961107.
20 .\"
21 .\" 2006-05-27, Several corrections - Thomas E. Dickey
22 .\"
23 .TH CONSOLE_CODES 4 2012-08-05 "Linux" "Linux Programmer's Manual"
24 .SH NAME
25 console_codes \- Linux console escape and control sequences
26 .SH DESCRIPTION
27 The Linux console implements a large subset of the VT102 and ECMA-48/ISO
28 6429/ANSI X3.64 terminal controls, plus certain private-mode sequences
29 for changing the color palette, character-set mapping, and so on.
30 In the tabular descriptions below, the second column gives ECMA-48 or DEC
31 mnemonics (the latter if prefixed with DEC) for the given function.
32 Sequences without a mnemonic are neither ECMA-48 nor VT102.
33 .LP
34 After all the normal output processing has been done, and a
35 stream of characters arrives at the console driver for actual
36 printing, the first thing that happens is a translation from
37 the code used for processing to the code used for printing.
38 .LP
39 If the console is in UTF-8 mode, then the incoming bytes are
40 first assembled into 16-bit Unicode codes.
41 Otherwise, each byte is transformed according to the current mapping table
42 (which translates it to a Unicode value).
43 See the \fBCharacter Sets\fP section below for discussion.
44 .LP
45 In the normal case, the Unicode value is converted to a font index,
46 and this is stored in video memory, so that the corresponding glyph
47 (as found in video ROM) appears on the screen.
48 Note that the use of Unicode (and the design of the PC hardware)
49 allows us to use 512 different glyphs simultaneously.
50 .LP
51 If the current Unicode value is a control character, or we are
52 currently processing an escape sequence, the value will treated
53 specially.
54 Instead of being turned into a font index and rendered as
55 a glyph, it may trigger cursor movement or other control functions.
56 See the \fBLinux Console Controls\fP section below for discussion.
57 .LP
58 It is generally not good practice to hard-wire terminal controls into
59 programs.
60 Linux supports a
61 .BR terminfo (5)
62 database of terminal capabilities.
63 Rather than emitting console escape sequences by hand, you will almost
64 always want to use a terminfo-aware screen library or utility such as
65 .BR ncurses (3),
66 .BR tput (1),
67 or
68 .BR reset (1).
69 .SS Linux console controls
70 This section describes all the control characters and escape sequences
71 that invoke special functions (i.e., anything other than writing a
72 glyph at the current cursor location) on the Linux console.
73 .PP
74 .B "Control characters"
75 .sp
76 A character is a control character if (before transformation
77 according to the mapping table) it has one of the 14 codes
78 00 (NUL), 07 (BEL), 08 (BS), 09 (HT), 0a (LF), 0b (VT),
79 0c (FF), 0d (CR), 0e (SO), 0f (SI), 18 (CAN), 1a (SUB),
80 1b (ESC), 7f (DEL).
81 One can set a "display control characters" mode (see below),
82 and allow 07, 09, 0b, 18, 1a, 7f to be displayed as glyphs.
83 On the other hand, in UTF-8 mode all codes 00-1f are regarded
84 as control characters, regardless of any "display control characters"
85 mode.
86 .PP
87 If we have a control character, it is acted upon immediately
88 and then discarded (even in the middle of an escape sequence)
89 and the escape sequence continues with the next character.
90 (However, ESC starts a new escape sequence, possibly aborting a previous
91 unfinished one, and CAN and SUB abort any escape sequence.)
92 The recognized control characters are BEL, BS, HT, LF, VT, FF,
93 CR, SO, SI, CAN, SUB, ESC, DEL, CSI.
94 They do what one would expect:
95 .HP
96 BEL (0x07, \fB^G\fP) beeps;
97 .HP
98 BS (0x08, \fB^H\fP) backspaces one column
99 (but not past the beginning of the line);
100 .HP
101 HT (0x09, \fB^I\fP) goes to the next tab stop or to the end of the line
102 if there is no earlier tab stop;
103 .HP
104 LF (0x0A, \fB^J\fP), VT (0x0B, \fB^K\fP) and
105 FF (0x0C, \fB^L\fP) all give a linefeed,
106 and if LF/NL (new-line mode) is set also a carriage return;
107 .HP
108 CR (0x0D, \fB^M\fP) gives a carriage return;
109 .HP
110 SO (0x0E, \fB^N\fP) activates the G1 character set;
111 .HP
112 SI (0x0F, \fB^O\fP) activates the G0 character set;
113 .HP
114 CAN (0x18, \fB^X\fP) and SUB (0x1A, \fB^Z\fP) interrupt escape sequences;
115 .HP
116 ESC (0x1B, \fB^[\fP) starts an escape sequence;
117 .HP
118 DEL (0x7F) is ignored;
119 .HP
120 CSI (0x9B) is equivalent to ESC [.
121 .PP
122 .B "ESC- but not CSI-sequences"
123 .TS
124 l l l.
125 ESC c RIS Reset.
126 ESC D IND Linefeed.
127 ESC E NEL Newline.
128 ESC H HTS Set tab stop at current column.
129 ESC M RI Reverse linefeed.
130 ESC Z DECID T{
131 DEC private identification. The kernel
132 returns the string ESC [ ? 6 c, claiming
133 that it is a VT102.
134 T}
135 ESC 7 DECSC T{
136 Save current state (cursor coordinates,
137 attributes, character sets pointed at by G0, G1).
138 T}
139 ESC 8 DECRC Restore state most recently saved by ESC 7.
140 ESC [ CSI Control sequence introducer
141 ESC % Start sequence selecting character set
142 ESC % @ \0\0\0Select default (ISO 646 / ISO 8859-1)
143 ESC % G \0\0\0Select UTF-8
144 ESC % 8 \0\0\0Select UTF-8 (obsolete)
145 ESC # 8 DECALN DEC screen alignment test \- fill screen with E's.
146 ESC ( Start sequence defining G0 character set
147 ESC ( B \0\0\0Select default (ISO 8859-1 mapping)
148 ESC ( 0 \0\0\0Select VT100 graphics mapping
149 ESC ( U \0\0\0Select null mapping \- straight to character ROM
150 ESC ( K \0\0\0Select user mapping \- the map that is loaded by
151 \0\0\0the utility \fBmapscrn\fP(8).
152 ESC ) Start sequence defining G1
153 (followed by one of B, 0, U, K, as above).
154 ESC > DECPNM Set numeric keypad mode
155 ESC = DECPAM Set application keypad mode
156 ESC ] OSC T{
157 (Should be: Operating system command)
158 ESC ] P \fInrrggbb\fP: set palette, with parameter
159 given in 7 hexadecimal digits after the final P :-(.
160 Here \fIn\fP is the color (0-15), and \fIrrggbb\fP indicates
161 the red/green/blue values (0-255).
162 ESC ] R: reset palette
163 T}
164 .TE
165 .PP
166 .B "ECMA-48 CSI sequences"
167 .sp
168 CSI (or ESC [) is followed by a sequence of parameters,
169 at most NPAR (16), that are decimal numbers separated by
170 semicolons.
171 An empty or absent parameter is taken to be 0.
172 The sequence of parameters may be preceded by a single question mark.
173 .PP
174 However, after CSI [ (or ESC [ [) a single character is read
175 and this entire sequence is ignored.
176 (The idea is to ignore an echoed function key.)
177 .PP
178 The action of a CSI sequence is determined by its final character.
179 .TS
180 l l l.
181 @ ICH Insert the indicated # of blank characters.
182 A CUU Move cursor up the indicated # of rows.
183 B CUD Move cursor down the indicated # of rows.
184 C CUF Move cursor right the indicated # of columns.
185 D CUB Move cursor left the indicated # of columns.
186 E CNL Move cursor down the indicated # of rows, to column 1.
187 F CPL Move cursor up the indicated # of rows, to column 1.
188 G CHA Move cursor to indicated column in current row.
189 H CUP Move cursor to the indicated row, column (origin at 1,1).
190 J ED Erase display (default: from cursor to end of display).
191 ESC [ 1 J: erase from start to cursor.
192 ESC [ 2 J: erase whole display.
193 ESC [ 3 J: erase whole display including scroll-back
194 buffer (since Linux 3.0).
195 .\" ESC [ 3 J: commit f8df13e0a901fe55631fed66562369b4dba40f8b
196 K EL Erase line (default: from cursor to end of line).
197 ESC [ 1 K: erase from start of line to cursor.
198 ESC [ 2 K: erase whole line.
199 L IL Insert the indicated # of blank lines.
200 M DL Delete the indicated # of lines.
201 P DCH Delete the indicated # of characters on current line.
202 X ECH Erase the indicated # of characters on current line.
203 a HPR Move cursor right the indicated # of columns.
204 c DA Answer ESC [ ? 6 c: "I am a VT102".
205 d VPA Move cursor to the indicated row, current column.
206 e VPR Move cursor down the indicated # of rows.
207 f HVP Move cursor to the indicated row, column.
208 g TBC Without parameter: clear tab stop at current position.
209 ESC [ 3 g: delete all tab stops.
210 h SM Set Mode (see below).
211 l RM Reset Mode (see below).
212 m SGR Set attributes (see below).
213 n DSR Status report (see below).
214 q DECLL Set keyboard LEDs.
215 ESC [ 0 q: clear all LEDs
216 ESC [ 1 q: set Scroll Lock LED
217 ESC [ 2 q: set Num Lock LED
218 ESC [ 3 q: set Caps Lock LED
219 r DECSTBM Set scrolling region; parameters are top and bottom row.
220 s ? Save cursor location.
221 u ? Restore cursor location.
222 \` HPA Move cursor to indicated column in current row.
223 .TE
224 .PP
225 .B ECMA-48 Set Graphics Rendition
226 .sp
227 The ECMA-48 SGR sequence ESC [ \fIparameters\fP m sets display
228 attributes.
229 Several attributes can be set in the same sequence, separated by
230 semicolons.
231 An empty parameter (between semicolons or string initiator or
232 terminator) is interpreted as a zero.
233 .TS
234 l l.
235 param result
236 0 reset all attributes to their defaults
237 1 set bold
238 2 set half-bright (simulated with color on a color display)
239 4 T{
240 set underscore (simulated with color on a color display)
241 (the colors used to simulate dim or underline are set
242 using ESC ] ...)
243 T}
244 5 set blink
245 7 set reverse video
246 10 T{
247 reset selected mapping, display control flag,
248 and toggle meta flag (ECMA-48 says "primary font").
249 T}
250 11 T{
251 select null mapping, set display control flag,
252 reset toggle meta flag (ECMA-48 says "first alternate font").
253 T}
254 12 T{
255 select null mapping, set display control flag,
256 set toggle meta flag (ECMA-48 says "second alternate font").
257 The toggle meta flag
258 causes the high bit of a byte to be toggled
259 before the mapping table translation is done.
260 T}
261 21 set normal intensity (ECMA-48 says "doubly underlined")
262 22 set normal intensity
263 24 underline off
264 25 blink off
265 27 reverse video off
266 30 set black foreground
267 31 set red foreground
268 32 set green foreground
269 33 set brown foreground
270 34 set blue foreground
271 35 set magenta foreground
272 36 set cyan foreground
273 37 set white foreground
274 38 set underscore on, set default foreground color
275 39 set underscore off, set default foreground color
276 40 set black background
277 41 set red background
278 42 set green background
279 43 set brown background
280 44 set blue background
281 45 set magenta background
282 46 set cyan background
283 47 set white background
284 49 set default background color
285 .TE
286 .PP
287 .B ECMA-48 Mode Switches
288 .TP
289 ESC [ 3 h
290 DECCRM (default off): Display control chars.
291 .TP
292 ESC [ 4 h
293 DECIM (default off): Set insert mode.
294 .TP
295 ESC [ 20 h
296 LF/NL (default off): Automatically follow echo of LF, VT or FF with CR.
297 .\"
298 .PP
299 .B ECMA-48 Status Report Commands
300 .\"
301 .TP
302 ESC [ 5 n
303 Device status report (DSR): Answer is ESC [ 0 n (Terminal OK).
304 .TP
305 ESC [ 6 n
306 Cursor position report (CPR): Answer is ESC [ \fIy\fP ; \fIx\fP R,
307 where \fIx,y\fP is the cursor location.
308 .\"
309 .PP
310 .B DEC Private Mode (DECSET/DECRST) sequences
311 .sp
312 .\"
313 These are not described in ECMA-48.
314 We list the Set Mode sequences;
315 the Reset Mode sequences are obtained by replacing the final \(aqh\(aq
316 by \(aql\(aq.
317 .TP
318 ESC [ ? 1 h
319 DECCKM (default off): When set, the cursor keys send an ESC O prefix,
320 rather than ESC [.
321 .TP
322 ESC [ ? 3 h
323 DECCOLM (default off = 80 columns): 80/132 col mode switch.
324 The driver sources note that this alone does not suffice; some user-mode
325 utility such as
326 .BR resizecons (8)
327 has to change the hardware registers on the console video card.
328 .TP
329 ESC [ ? 5 h
330 DECSCNM (default off): Set reverse-video mode.
331 .TP
332 ESC [ ? 6 h
333 DECOM (default off): When set, cursor addressing is relative to
334 the upper left corner of the scrolling region.
335 .TP
336 ESC [ ? 7 h
337 DECAWM (default on): Set autowrap on.
338 In this mode, a graphic
339 character emitted after column 80 (or column 132 of DECCOLM is on)
340 forces a wrap to the beginning of the following line first.
341 .TP
342 ESC [ ? 8 h
343 DECARM (default on): Set keyboard autorepeat on.
344 .TP
345 ESC [ ? 9 h
346 X10 Mouse Reporting (default off): Set reporting mode to 1 (or reset to
347 0)\(emsee below.
348 .TP
349 ESC [ ? 25 h
350 DECTECM (default on): Make cursor visible.
351 .TP
352 ESC [ ? 1000 h
353 X11 Mouse Reporting (default off): Set reporting mode to 2 (or reset
354 to 0)\(emsee below.
355 .\"
356 .PP
357 .B Linux Console Private CSI Sequences
358 .sp
359 .\"
360 The following sequences are neither ECMA-48 nor native VT102.
361 They are native to the Linux console driver.
362 Colors are in SGR parameters:
363 0 = black, 1 = red, 2 = green, 3 = brown, 4 = blue, 5 = magenta, 6 =
364 cyan, 7 = white.
365 .TS
366 l l.
367 ESC [ 1 ; \fIn\fP ] Set color \fIn\fP as the underline color
368 ESC [ 2 ; \fIn\fP ] Set color \fIn\fP as the dim color
369 ESC [ 8 ] Make the current color pair the default attributes.
370 ESC [ 9 ; \fIn\fP ] Set screen blank timeout to \fIn\fP minutes.
371 ESC [ 10 ; \fIn\fP ] Set bell frequency in Hz.
372 ESC [ 11 ; \fIn\fP ] Set bell duration in msec.
373 ESC [ 12 ; \fIn\fP ] Bring specified console to the front.
374 ESC [ 13 ] Unblank the screen.
375 ESC [ 14 ; \fIn\fP ] Set the VESA powerdown interval in minutes.
376 .TE
377 .SS Character sets
378 The kernel knows about 4 translations of bytes into console-screen
379 symbols.
380 The four tables are: a) Latin1 \-> PC,
381 b) VT100 graphics \-> PC, c) PC \-> PC, d) user-defined.
382 .PP
383 There are two character sets, called G0 and G1, and one of them
384 is the current character set.
385 (Initially G0.)
386 Typing \fB^N\fP causes G1 to become current,
387 \fB^O\fP causes G0 to become current.
388 .PP
389 These variables G0 and G1 point at a translation table, and can be
390 changed by the user.
391 Initially they point at tables a) and b), respectively.
392 The sequences ESC ( B and ESC ( 0 and ESC ( U and ESC ( K cause G0 to
393 point at translation table a), b), c) and d), respectively.
394 The sequences ESC ) B and ESC ) 0 and ESC ) U and ESC ) K cause G1 to
395 point at translation table a), b), c) and d), respectively.
396 .PP
397 The sequence ESC c causes a terminal reset, which is what you want if the
398 screen is all garbled.
399 The oft-advised "echo ^V^O" will make only G0 current,
400 but there is no guarantee that G0 points at table a).
401 In some distributions there is a program
402 .BR reset (1)
403 that just does "echo ^[c".
404 If your terminfo entry for the console is correct
405 (and has an entry rs1=\\Ec), then "tput reset" will also work.
406 .PP
407 The user-defined mapping table can be set using
408 .BR mapscrn (8).
409 The result of the mapping is that if a symbol c is printed, the symbol
410 s = map[c] is sent to the video memory.
411 The bitmap that corresponds to
412 s is found in the character ROM, and can be changed using
413 .BR setfont (8).
414 .SS Mouse tracking
415 The mouse tracking facility is intended to return
416 .BR xterm (1)-compatible
417 mouse status reports.
418 Because the console driver has no way to know
419 the device or type of the mouse, these reports are returned in the
420 console input stream only when the virtual terminal driver receives
421 a mouse update ioctl.
422 These ioctls must be generated by a mouse-aware
423 user-mode application such as the
424 .BR gpm (8)
425 daemon.
426 .PP
427 The mouse tracking escape sequences generated by
428 \fBxterm\fP(1) encode numeric parameters in a single character as
429 \fIvalue\fP+040.
430 For example, \(aq!\(aq is 1.
431 The screen coordinate system is 1-based.
432 .PP
433 The X10 compatibility mode sends an escape sequence on button press
434 encoding the location and the mouse button pressed.
435 It is enabled by sending ESC [ ? 9 h and disabled with ESC [ ? 9 l.
436 On button press, \fBxterm\fP(1) sends
437 ESC [ M \fIbxy\fP (6 characters).
438 Here \fIb\fP is button\-1,
439 and \fIx\fP and \fIy\fP are the x and y coordinates of the mouse
440 when the button was pressed.
441 This is the same code the kernel also produces.
442 .PP
443 Normal tracking mode (not implemented in Linux 2.0.24) sends an escape
444 sequence on both button press and release.
445 Modifier information is also sent.
446 It is enabled by sending ESC [ ? 1000 h and disabled with
447 ESC [ ? 1000 l.
448 On button press or release, \fBxterm\fP(1) sends ESC [ M
449 \fIbxy\fP.
450 The low two bits of \fIb\fP encode button information:
451 0=MB1 pressed, 1=MB2 pressed, 2=MB3 pressed, 3=release.
452 The upper bits encode what modifiers were down when the button was
453 pressed and are added together: 4=Shift, 8=Meta, 16=Control.
454 Again \fIx\fP and
455 \fIy\fP are the x and y coordinates of the mouse event.
456 The upper left corner is (1,1).
457 .SS Comparisons with other terminals
458 Many different terminal types are described, like the Linux console,
459 as being "VT100-compatible".
460 Here we discuss differences between the
461 Linux console and the two most important others, the DEC VT102 and
462 .BR xterm (1).
463 .\"
464 .PP
465 .B Control-character handling
466 .sp
467 The VT102 also recognized the following control characters:
468 .HP
469 NUL (0x00) was ignored;
470 .HP
471 ENQ (0x05) triggered an answerback message;
472 .HP
473 DC1 (0x11, \fB^Q\fP, XON) resumed transmission;
474 .HP
475 DC3 (0x13, \fB^S\fP, XOFF) caused VT100 to ignore (and stop transmitting)
476 all codes except XOFF and XON.
477 .LP
478 VT100-like DC1/DC3 processing may be enabled by the terminal driver.
479 .LP
480 The
481 .BR xterm (1)
482 program (in VT100 mode) recognizes the control characters
483 BEL, BS, HT, LF, VT, FF, CR, SO, SI, ESC.
484 .\"
485 .PP
486 .B Escape sequences
487 .sp
488 VT100 console sequences not implemented on the Linux console:
489 .TS
490 l l l.
491 ESC N SS2 Single shift 2. (Select G2 character set for the next
492 character only.)
493 ESC O SS3 Single shift 3. (Select G3 character set for the next
494 character only.)
495 ESC P DCS Device control string (ended by ESC \\)
496 ESC X SOS Start of string.
497 ESC ^ PM Privacy message (ended by ESC \\)
498 ESC \\ ST String terminator
499 ESC * ... Designate G2 character set
500 ESC + ... Designate G3 character set
501 .TE
502 .PP
503 The program
504 .BR xterm (1)
505 (in VT100 mode) recognizes ESC c, ESC # 8, ESC >, ESC =,
506 ESC D, ESC E, ESC H, ESC M, ESC N, ESC O, ESC P ... ESC \\,
507 ESC Z (it answers ESC [ ? 1 ; 2 c, "I am a VT100 with
508 advanced video option")
509 and ESC ^ ... ESC \\ with the same meanings as indicated above.
510 It accepts ESC (, ESC ), ESC *, ESC + followed by 0, A, B for
511 the DEC special character and line drawing set, UK, and US-ASCII,
512 respectively.
513 .PP
514 The user can configure \fBxterm\fP(1) to respond to VT220-specific
515 control sequences, and it will identify itself as a VT52, VT100, and
516 up depending on the way it is configured and initialized.
517 .PP
518 It accepts ESC ] (OSC) for the setting of certain resources.
519 In addition to the ECMA-48 string terminator (ST),
520 \fBxterm\fP(1) accepts a BEL to terminate an OSC string.
521 These are a few of the OSC control sequences recognized by \fBxterm\fP(1):
522 .TS
523 l l.
524 ESC ] 0 ; \fItxt\fP ST Set icon name and window title to \fItxt\fP.
525 ESC ] 1 ; \fItxt\fP ST Set icon name to \fItxt\fP.
526 ESC ] 2 ; \fItxt\fP ST Set window title to \fItxt\fP.
527 ESC ] 4 ; \fInum\fP; \fItxt\fP ST Set ANSI color \fInum\fP to \fItxt\fP.
528 ESC ] 10 ; \fItxt\fP ST Set dynamic text color to \fItxt\fP.
529 ESC ] 4 6 ; \fIname\fP ST Change log file to \fIname\fP (normally disabled
530 by a compile-time option)
531 ESC ] 5 0 ; \fIfn\fP ST Set font to \fIfn\fP.
532 .TE
533 .PP
534 It recognizes the following with slightly modified meaning
535 (saving more state, behaving closer to VT100/VT220):
536 .TS
537 l l l.
538 ESC 7 DECSC Save cursor
539 ESC 8 DECRC Restore cursor
540 .TE
541 .PP
542 It also recognizes
543 .TS
544 l l l.
545 ESC F Cursor to lower left corner of screen (if enabled by
546 \fBxterm\fP(1)'s \fBhpLowerleftBugCompat\fP resource)
547 ESC l Memory lock (per HP terminals).
548 Locks memory above the cursor.
549 ESC m Memory unlock (per HP terminals).
550 ESC n LS2 Invoke the G2 character set.
551 ESC o LS3 Invoke the G3 character set.
552 ESC | LS3R Invoke the G3 character set as GR.
553 ESC } LS2R Invoke the G2 character set as GR.
554 ESC ~ LS1R Invoke the G1 character set as GR.
555 .TE
556 .PP
557 It also recognizes ESC % and provides a more complete UTF-8
558 implementation than Linux console.
559 .\"
560 .PP
561 .B CSI Sequences
562 .sp
563 Old versions of \fBxterm\fP(1), for example, from X11R5,
564 interpret the blink SGR as a bold SGR.
565 Later versions which implemented ANSI colors, for example,
566 XFree86 3.1.2A in 1995, improved this by allowing
567 the blink attribute to be displayed as a color.
568 Modern versions of xterm implement blink SGR as blinking text
569 and still allow colored text as an alternate rendering of SGRs.
570 Stock X11R6 versions did not recognize the color-setting SGRs until
571 the X11R6.8 release, which incorporated XFree86 xterm.
572 All ECMA-48 CSI sequences recognized by Linux are also recognized by
573 .IR xterm ,
574 however \fBxterm\fP(1) implements several ECMA-48 and DEC control sequences
575 not recognized by Linux.
576 .PP
577 The \fBxterm\fP(1)
578 program recognizes all of the DEC Private Mode sequences listed
579 above, but none of the Linux private-mode sequences.
580 For discussion of \fBxterm\fP(1)'s
581 own private-mode sequences, refer to the
582 \fIXterm Control Sequences\fP
583 document by
584 Edward Moy,
585 Stephen Gildea,
586 and Thomas E. Dickey
587 available with the X distribution.
588 That document, though terse, is much longer than this manual page.
589 For a chronological overview,
590 .PP
591 .RS
592 .UR http://invisible-island.net\:/xterm\:/xterm.log.html
593 .UE
594 .RE
595 .PP
596 details changes to xterm.
597 .PP
598 The \fIvttest\fP program
599 .PP
600 .RS
601 .UR http://invisible-island.net\:/vttest/
602 .UE
603 .RE
604 .PP
605 demonstrates many of these control sequences.
606 The \fBxterm\fP(1) source distribution also contains sample
607 scripts which exercise other features.
608 .SH NOTES
609 ESC 8 (DECRC) is not able to restore the character set changed with
610 ESC %.
611 .SH BUGS
612 In 2.0.23, CSI is broken, and NUL is not ignored inside
613 escape sequences.
614 .PP
615 Some older kernel versions (after 2.0) interpret 8-bit control
616 sequences.
617 These "C1 controls" use codes between 128 and 159 to replace
618 ESC [, ESC ] and similar two-byte control sequence initiators.
619 There are fragments of that in modern kernels (either overlooked or
620 broken by changes to support UTF-8),
621 but the implementation is incomplete and should be regarded
622 as unreliable.
623 .PP
624 Linux "private mode" sequences do not follow the rules in ECMA-48
625 for private mode control sequences.
626 In particular, those ending with ] do not use a standard terminating
627 character.
628 The OSC (set palette) sequence is a greater problem,
629 since \fBxterm\fP(1) may interpret this as a control sequence
630 which requires a string terminator (ST).
631 Unlike the \fBsetterm\fP(1) sequences which will be ignored (since
632 they are invalid control sequences), the palette sequence will make
633 \fBxterm\fP(1) appear to hang (though pressing the return-key
634 will fix that).
635 To accommodate applications which have been hardcoded to use Linux
636 control sequences,
637 set the \fBxterm\fP(1) resource \fBbrokenLinuxOSC\fP to true.
638 .PP
639 An older version of this document implied that Linux recognizes the
640 ECMA-48 control sequence for invisible text.
641 It is ignored.
642 .SH SEE ALSO
643 .BR console (4),
644 .BR console_ioctl (4),
645 .BR charsets (7)