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diff --git a/man4/console_codes.4 b/man4/console_codes.4 new file mode 100644 index 000000000..2df2cc0ea --- /dev/null +++ b/man4/console_codes.4 @@ -0,0 +1,526 @@ +'\" t +.\" Copyright (c) 1996 Andries Brouwer <aeb@cwi.nl>, Mon Oct 31 22:13:04 1996 +.\" +.\" This is free documentation; you can redistribute it and/or +.\" modify it under the terms of the GNU General Public License as +.\" published by the Free Software Foundation; either version 2 of +.\" the License, or (at your option) any later version. +.\" +.\" This is combined from many sources. +.\" For Linux, the definitive source is of course console.c. +.\" About vt100-like escape sequences in general there are +.\" the ISO 6429 and ISO 2022 norms, the descriptions of +.\" an actual vt100, and the xterm docs (ctlseqs.ms). +.\" Substantial portions of this text are derived from a write-up +.\" by Eric S. Raymond <esr@thyrsus.com>. +.\" +.\" Tiny correction, aeb, 961107. +.\" +.TH CONSOLE_CODES 4 1996-10-31 "Linux" "Linux Programmer's Manual" +.SH NAME +console_codes \- Linux console escape and control sequences +.SH DESCRIPTION +The Linux console implements a large subset of the VT102 and ECMA-48/ISO +6429/ANSI X3.64 terminal controls, plus certain private-mode sequences +for changing the color palette, character-set mapping, etc. +In the tabular descriptions below, the second column gives ECMA-48 or DEC +mnemonics (the latter if prefixed with DEC) for the given function. +Sequences without a mnemonic are neither ECMA-48 nor VT102. +.LP +After all the normal output processing has been done, and a +stream of characters arrives at the console driver for actual +printing, the first thing that happens is a translation from +the code used for processing to the code used for printing. +.LP +If the console is in UTF-8 mode, then the incoming bytes are +first assembled into 16-bit Unicode codes. Otherwise +each byte is transformed according to the current mapping table +(which translates it to a Unicode value). See the CHARACTER SETS +section below for discussion. +.LP +In the normal case, the Unicode value is converted to a font index, +and this is stored in video memory, so that the corresponding glyph +(as found in video ROM) appears on the screen. +Note that the use of Unicode (and the design of the PC hardware) +allows us to use 512 different glyphs simultaneously. +.LP +If the current Unicode value is a control character, or we are +currently processing an escape sequence, the value will treated +specially. Instead of being turned into a font index and rendered as +a glyph, it may trigger cursor movement or other control functions. +See the LINUX CONSOLE CONTROLS section below for discussion. +.LP +It is generally not good practice to hard-wire terminal controls into +programs. Linux supports a +.BR terminfo (5) +database of terminal capabilities. +Rather than emitting console escape sequences by hand, you will almost +always want to use a terminfo-aware screen library or utility such as +.BR ncurses (3), +.BR tput (1), +or +.BR reset (1). + +.SH "LINUX CONSOLE CONTROLS" + +This section describes all the control characters and escape sequences +that invoke special functions (i.e. anything other than writing a +glyph at the current cursor location) on the Linux console. +.SS "Control characters" +A character is a control character if (before transformation +according to the mapping table) it has one of the 14 codes +00 (NUL), 07 (BEL), 08 (BS), 09 (HT), 0a (LF), 0b (VT), +0c (FF), 0d (CR), 0e (SO), 0f (SI), 18 (CAN), 1a (SUB), +1b (ESC), 7f (DEL). +One can set a `display control characters' mode (see below), +and allow 07, 09, 0b, 18, 1a, 7f to be displayed as glyphs. +On the other hand, in UTF-8 mode all codes 00-1f are regarded +as control characters, regardless of any `display control characters' +mode. + +If we have a control character, it is acted upon immediately +and then discarded (even in the middle of an escape sequence) +and the escape sequence continues with the next character. +(However, ESC starts a new escape sequence, possibly aborting a previous +unfinished one, and CAN and SUB abort any escape sequence.) +The recognized control characters are BEL, BS, HT, LF, VT, FF, +CR, SO, SI, CAN, SUB, ESC, DEL, CSI. They do what one would expect: +.HP +BEL (0x07, ^G) beeps; +.HP +BS (0x08, ^H) backspaces one column +(but not past the beginning of the line); +.HP +HT (0x09, ^I) goes to the next tab stop or to the end of the line +if there is no earlier tab stop; +.HP +LF (0x0A, ^J), VT (0x0B, ^K) and FF (0x0C, ^L) all give a linefeed; +.HP +CR (0x0D, ^M) gives a carriage return; +.HP +SO (0x0E, ^N) activates the G1 character set, +and if LF/NL (new line mode) is set also a carriage return; +.HP +SI (0x0F, ^O) activates the G0 character set; +.HP +CAN (0x18, ^X) and SUB (0x1A, ^Z) interrupt escape sequences; +.HP +ESC (0x1B, ^[) starts an escape sequence; +.HP +DEL (0x7F) is ignored; +.HP +CSI (0x9B) is equivalent to ESC [. +.\" .LP +.SS "ESC- but not CSI-sequences" +.TS +l l l. +ESC c RIS Reset. +ESC D IND Linefeed. +ESC E NEL Newline. +ESC H HTS Set tab stop at current column. +ESC M RI Reverse linefeed. +ESC Z DECID DEC private identification. The kernel + returns the string ESC [ ? 6 c, claiming + that it is a VT102. +ESC 7 DECSC Save current state (cursor coordinates, + attributes, character sets pointed at by G0, G1). +ESC 8 DECRC Restore state most recently saved by ESC 7. +ESC [ CSI Control sequence introducer +ESC % Start sequence selecting character set +ESC % @ \0\0\0Select default (ISO 646 / ISO 8859-1) +ESC % G \0\0\0Select UTF-8 +ESC % 8 \0\0\0Select UTF-8 (obsolete) +ESC # 8 DECALN DEC screen alignment test - fill screen with E's. +ESC ( Start sequence defining G0 character set +ESC ( B \0\0\0Select default (ISO 8859-1 mapping) +ESC ( 0 \0\0\0Select vt100 graphics mapping +ESC ( U \0\0\0Select null mapping - straight to character ROM +ESC ( K \0\0\0Select user mapping - the map that is loaded by + \0\0\0the utility \fBmapscrn\fP(8). +ESC ) Start sequence defining G1 + (followed by one of B, 0, U, K, as above). +ESC > DECPNM Set numeric keypad mode +ESC = DECPAM Set application keypad mode +ESC ] OSC (Should be: Operating system command) + ESC ] P \fInrrggbb\fP: set palette, with parameter + given in 7 hexadecimal digits after the final P :-(. + Here \fIn\fP is the color (0-15), and \fIrrggbb\fP indicates + the red/green/blue values (0-255). + ESC ] R: reset palette +.TE +.SS "ECMA-48 CSI sequences" + +CSI (or ESC [) is followed by a sequence of parameters, +at most NPAR (16), that are decimal numbers separated by +semicolons. An empty or absent parameter is taken to be 0. +The sequence of parameters may be preceded by a single question mark. + +However, after CSI [ (or ESC [ [) a single character is read +and this entire sequence is ignored. (The idea is to ignore +an echoed function key.) + +The action of a CSI sequence is determined by its final character. + +.TS +l l l. +@ ICH Insert the indicated # of blank characters. +A CUU Move cursor up the indicated # of rows. +B CUD Move cursor down the indicated # of rows. +C CUF Move cursor right the indicated # of columns. +D CUB Move cursor left the indicated # of columns. +E CNL Move cursor down the indicated # of rows, to column 1. +F CPL Move cursor up the indicated # of rows, to column 1. +G CHA Move cursor to indicated column in current row. +H CUP Move cursor to the indicated row, column (origin at 1,1). +J ED Erase display (default: from cursor to end of display). + ESC [ 1 J: erase from start to cursor. + ESC [ 2 J: erase whole display. +K EL Erase line (default: from cursor to end of line). + ESC [ 1 K: erase from start of line to cursor. + ESC [ 2 K: erase whole line. +L IL Insert the indicated # of blank lines. +M DL Delete the indicated # of lines. +P DCH Delete the indicated # of characters on the current line. +X ECH Erase the indicated # of characters on the current line. +a HPR Move cursor right the indicated # of columns. +c DA Answer ESC [ ? 6 c: `I am a VT102'. +d VPA Move cursor to the indicated row, current column. +e VPR Move cursor down the indicated # of rows. +f HVP Move cursor to the indicated row, column. +g TBC Without parameter: clear tab stop at the current position. + ESC [ 3 g: delete all tab stops. +h SM Set Mode (see below). +l RM Reset Mode (see below). +m SGR Set attributes (see below). +n DSR Status report (see below). +q DECLL Set keyboard LEDs. + ESC [ 0 q: clear all LEDs + ESC [ 1 q: set Scroll Lock LED + ESC [ 2 q: set Num Lock LED + ESC [ 3 q: set Caps Lock LED +r DECSTBM Set scrolling region; parameters are top and bottom row. +s ? Save cursor location. +u ? Restore cursor location. +` HPA Move cursor to indicated column in current row. +.TE +.SS ECMA-48 Set Graphics Rendition + +The ECMA-48 SGR sequence ESC [ <parameters> m sets display attributes. +Several attributes can be set in the same sequence. +.LP +.TS +l l. +par result +0 reset all attributes to their defaults +1 set bold +2 set half-bright (simulated with color on a color display) +4 set underscore (simulated with color on a color display) + (the colors used to simulate dim or underline are set + using ESC ] ...) +5 set blink +7 set reverse video +10 reset selected mapping, display control flag, + and toggle meta flag. +11 select null mapping, set display control flag, + reset toggle meta flag. +12 select null mapping, set display control flag, + set toggle meta flag. (The toggle meta flag + causes the high bit of a byte to be toggled + before the mapping table translation is done.) +21 set normal intensity (this is not compatible with ECMA-48) +22 set normal intensity +24 underline off +25 blink off +27 reverse video off +30 set black foreground +31 set red foreground +32 set green foreground +33 set brown foreground +34 set blue foreground +35 set magenta foreground +36 set cyan foreground +37 set white foreground +38 set underscore on, set default foreground color +39 set underscore off, set default foreground color +40 set black background +41 set red background +42 set green background +43 set brown background +44 set blue background +45 set magenta background +46 set cyan background +47 set white background +49 set default background color +.TE +.SS ECMA-48 Mode Switches +.TP +ESC [ 3 h +DECCRM (default off): Display control chars. +.TP +ESC [ 4 h +DECIM (default off): Set insert mode. +.TP +ESC [ 20 h +LF/NL (default off): Automatically follow echo of LF, VT or FF with CR. +.\" +.SS ECMA-48 Status Report Commands +.\" +.TP +ESC [ 5 n +Device status report (DSR): Answer is ESC [ 0 n (Terminal OK). +.TP +ESC [ 6 n +Cursor position report (CPR): Answer is ESC [ \fIy\fP ; \fIx\fP R, +where \fIx,y\fP is the cursor location. +.\" +.SS DEC Private Mode (DECSET/DECRST) sequences. +.\" +These are not described in ECMA-48. We list the Set Mode sequences; +the Reset Mode sequences are obtained by replacing the final `h' +by `l'. +.TP +ESC [ ? 1 h +DECCKM (default off): When set, the cursor keys send an ESC O prefix, +rather than ESC [. +.TP +ESC [ ? 3 h +DECCOLM (default off = 80 columns): 80/132 col mode switch. The +driver sources note that this alone does not suffice; some user-mode +utility such as +.BR resizecons (8) +has to change the hardware registers on the console video card. +.TP +ESC [ ? 5 h +DECSCNM (default off): Set reverse-video mode. +.TP +ESC [ ? 6 h +DECOM (default off): When set, cursor addressing is relative to +the upper left corner of the scrolling region. +.TP +ESC [ ? 7 h +DECAWM (default on): Set autowrap on. In this mode, a graphic +character emitted after column 80 (or column 132 of DECCOLM is on) +forces a wrap to the beginning of the following line first. +.TP +ESC [ ? 8 h +DECARM (default on): Set keyboard autorepreat on. +.TP +ESC [ ? 9 h +X10 Mouse Reporting (default off): Set reporting mode to 1 (or reset to +0) \- see below. +.TP +ESC [ ? 25 h +DECCM (default on): Make cursor visible. +.TP +ESC [ ? 1000 h +X11 Mouse Reporting (default off): Set reporting mode to 2 (or reset +to 0) \- see below. +.\" +.SS Linux Console Private CSI Sequences +.\" +The following sequences are neither ECMA-48 nor native VT102. They +are native to the Linux console driver. Colors are in SGR parameters: +0 = black, 1 = red, 2 = green, 3 = brown, 4 = blue, 5 = magenta, 6 = +cyan, 7 = white. + +.TS +l l. +ESC [ 1 ; \fIn\fP ] Set color \fIn\fP as the underline color +ESC [ 2 ; \fIn\fP ] Set color \fIn\fP as the dim color +ESC [ 8 ] Make the current color pair the default attributes. +ESC [ 9 ; \fIn\fP ] Set screen blank timeout to \fIn\fP minutes. +ESC [ 10 ; \fIn\fP ] Set bell frequency in Hz. +ESC [ 11 ; \fIn\fP ] Set bell duration in msec. +ESC [ 12 ; \fIn\fP ] Bring specified console to the front. +ESC [ 13 ] Unblank the screen. +ESC [ 14 ; \fIn\fP ] Set the VESA powerdown interval in minutes. +.TE + +.SH "CHARACTER SETS" + +The kernel knows about 4 translations of bytes into console-screen symbols. +The four tables are: a) Latin1 -> PC, b) VT100 graphics -> PC, c) PC -> PC, +d) user-defined. + +There are two character sets, called G0 and G1, and one of them +is the current character set. (Initially G0.) +Typing ^N causes G1 to become current, ^O causes G0 to become current. + +These variables G0 and G1 point at a translation table, and can be changed +by the user. Initially they point at tables a) and b), respectively. +The sequences ESC ( B and ESC ( 0 and ESC ( U and ESC ( K cause G0 to point +at translation table a), b), c) and d), respectively. +The sequences ESC ) B and ESC ) 0 and ESC ) U and ESC ) K cause G1 to point +at translation table a), b), c) and d), respectively. + +The sequence ESC c causes a terminal reset, which is what you want if the +screen is all garbled. The oft-advised "echo ^V^O" will only make G0 current, +but there is no guarantee that G0 points at table a). +In some distributions there is a program +.BR reset (1) +that just does "echo ^[c". +If your terminfo entry for the console is correct (and has an entry rs1=\\Ec), +then "tput reset" will also work. + +The user-defined mapping table can be set using +.BR mapscrn (8). +The result of the mapping is that if a symbol c is printed, the symbol +s = map[c] is sent to the video memory. The bitmap that corresponds to +s is found in the character ROM, and can be changed using +.BR setfont(8). + +.SH "MOUSE TRACKING" + +The mouse tracking facility is intended to return xterm-compatible +mouse status reports. Because the console driver has no way to know +the device or type of the mouse, these reports are returned in the +console input stream only when the virtual terminal driver receives +a mouse update ioctl. These ioctls must be generated by a mouse-aware +user-mode application such as the \fBgpm(8)\fR daemon. + +Parameters for all mouse tracking escape sequences generated by +\fIxterm\fP encode numeric parameters in a single character as +\fIvalue\fP+040. For example, `!' is 1. The screen +coordinate system is 1-based. + +The X10 compatibility mode sends an escape sequence on button press +encoding the location and the mouse button pressed. +It is enabled by sending ESC [ ? 9 h and disabled with ESC [ ? 9 l. +On button press, \fIxterm\fP sends +ESC [ M \fIbxy\fP (6 characters). Here \fIb\fP is button\-1, +and \fIx\fP and \fIy\fP are the x and y coordinates of the mouse +when the button was pressed. +This is the same code the kernel also produces. + +Normal tracking mode (not implemented in Linux 2.0.24) sends an escape +sequence on both button press and release. Modifier information is +also sent. It is enabled by sending ESC [ ? 1000 h and disabled with +ESC [ 1000 l. On button press or release, \fIxterm\fP sends ESC [ M +\fIbxy\fP. The low two bits of \fIb\fP encode button information: +0=MB1 pressed, 1=MB2 pressed, 2=MB3 pressed, 3=release. The upper +bits encode what modifiers were down when the button was pressed and +are added together: 4=Shift, 8=Meta, 16=Control. Again \fIx\fP and +\fIy\fP are the x and y coordinates of the mouse event. The upper +left corner is (1,1). + +.SH "COMPARISONS WITH OTHER TERMINALS" + +Many different terminal types are described, like the Linux console, +as being `VT100-compatible'. Here we discuss differences vbetween the +Linux console an the two most important others, the DEC VT102 and +.BR xterm (1). +.\" +.SS Control-character handling +The vt102 also recognized the following control characters: +.HP +NUL (0x00) was ignored; +.HP +ENQ (0x05) triggered an answerback message; +.HP +DC1 (0x11, ^Q, XON) resumed transmission; +.HP +DC3 (0x13, ^S, XOFF) caused vt100 to ignore (and stop transmitting) +all codes except XOFF and XON. +.LP +VT100-like DC1/DC3 processing may be enabled by the tty driver. +.LP +The +.I xterm +program (in vt100 mode) recognizes the control characters +BEL, BS, HT, LF, VT, FF, CR, SO, SI, ESC. +.\" +.SS Escape sequences +VT100 console sequences not implemented on the Linux console: +.LP +.TS +l l l. +ESC N SS2 Single shift 2. (Select G2 character set for the next + character only.) +ESC O SS3 Single shift 3. (Select G3 character set for the next + character only.) +ESC P DCS Device control string (ended by ESC \e) +ESC X SOS Start of string. +ESC ^ PM Privacy message (ended by ESC \e) +ESC \e ST String terminator +ESC * ... Designate G2 character set +ESC + ... Designate G3 character set +.TE + +The program +.I xterm +(in vt100 mode) recognizes ESC c, ESC # 8, ESC >, ESC =, +ESC D, ESC E, ESC H, ESC M, ESC N, ESC O, ESC P ... ESC \, +ESC Z (it answers ESC [ ? 1 ; 2 c, `I am a vt100 with advanced video option') +and ESC ^ ... ESC \ with the same meanings as indicated above. +It accepts ESC (, ESC ), ESC *, ESC + followed by 0, A, B for +the DEC special character and line drawing set, UK, and USASCII, +respectively. +It accepts ESC ] for the setting of certain resources: +.LP +.TS +l l. +ESC ] 0 ; txt BEL Set icon name and window title to txt. +ESC ] 1 ; txt BEL Set icon name to txt. +ESC ] 2 ; txt BEL Set window title to txt. +ESC ] 4 6 ; name BEL Change log file to name (normally disabled + by a compile-time option) +ESC ] 5 0 ; fn BEL Set font to fn. +.TE + +It recognizes the following with slightly modified meaning: +.LP +.TS +l l l. +ESC 7 DECSC Save cursor +ESC 8 DECRC Restore cursor +.TE + +It also recognizes +.LP +.TS +l l l. +ESC F Cursor to lower left corner of screen (if enabled by + the hpLowerleftBugCompat resource) +ESC l Memory lock (per HP terminals). + Locks memory above the cursor. +ESC m Memory unlock (per HP terminals). +ESC n LS2 Invoke the G2 character set. +ESC o LS3 Invoke the G3 character set. +ESC | LS3R Invoke the G3 character set as GR. + Has no visible effect in xterm. +ESC } LS2R Invoke the G2 character set as GR. + Has no visible effect in xterm. +ESC ~ LS1R Invoke the G1 character set as GR. + Has no visible effect in xterm. +.TE + +It does not recognize ESC % ... +.\" +.SS CSI Sequences +The +.I xterm +program (as of XFree86 3.1.2G) does not recognize the blink or invisible-mode +SGRs. Stock X11R6 versions do not recognize the color-setting SGRs. +All other ECMA-48 CSI sequences recognized by Linux are also recognized by +.IR xterm , +and vice-versa. + +The +.I xterm +program will recognize all of the DEC Private Mode sequences listed +above, but none of the Linux private-mode sequences. For discussion +of +.IR xterm 's +own private-mode sequences, refer to the +.I Xterm Control Sequences +document by Edward Moy and Stephen Gildea, available with the X +distribution. + +.SH BUGS + +In 2.0.23, CSI is broken, and NUL is not ignored inside escape sequences. + +.SH "SEE ALSO" +.BR console (4), +.BR console_ioctl (4), +.BR charsets (7) |