mirror of https://github.com/mkerrisk/man-pages
793 lines
23 KiB
Groff
793 lines
23 KiB
Groff
.\" Copyright (c) 1996 Andries Brouwer <aeb@cwi.nl>, Mon Oct 31 22:13:04 1996
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.\"
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.\" %%%LICENSE_START(GPLv2+_DOC_ONEPARA)
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.\" This is free documentation; you can redistribute it and/or
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.\" modify it under the terms of the GNU General Public License as
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.\" published by the Free Software Foundation; either version 2 of
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.\" the License, or (at your option) any later version.
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.\" %%%LICENSE_END
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.\"
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.\" This is combined from many sources.
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.\" For Linux, the definitive source is of course console.c.
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.\" About vt100-like escape sequences in general there are
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.\" the ISO 6429 and ISO 2022 norms, the descriptions of
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.\" an actual vt100, and the xterm docs (ctlseqs.ms).
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.\" Substantial portions of this text are derived from a write-up
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.\" by Eric S. Raymond <esr@thyrsus.com>.
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.\"
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.\" Tiny correction, aeb, 961107.
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.\"
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.\" 2006-05-27, Several corrections - Thomas E. Dickey
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.\"
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.TH CONSOLE_CODES 4 2021-03-22 "Linux" "Linux Programmer's Manual"
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.SH NAME
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console_codes \- Linux console escape and control sequences
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.SH DESCRIPTION
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The Linux console implements a large subset of the VT102 and ECMA-48/ISO
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6429/ANSI X3.64 terminal controls, plus certain private-mode sequences
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for changing the color palette, character-set mapping, and so on.
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In the tabular descriptions below, the second column gives ECMA-48 or DEC
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mnemonics (the latter if prefixed with DEC) for the given function.
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Sequences without a mnemonic are neither ECMA-48 nor VT102.
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.PP
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After all the normal output processing has been done, and a
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stream of characters arrives at the console driver for actual
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printing, the first thing that happens is a translation from
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the code used for processing to the code used for printing.
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.PP
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If the console is in UTF-8 mode, then the incoming bytes are
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first assembled into 16-bit Unicode codes.
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Otherwise, each byte is transformed according to the current mapping table
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(which translates it to a Unicode value).
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See the \fBCharacter Sets\fP section below for discussion.
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.PP
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In the normal case, the Unicode value is converted to a font index,
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and this is stored in video memory, so that the corresponding glyph
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(as found in video ROM) appears on the screen.
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Note that the use of Unicode (and the design of the PC hardware)
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allows us to use 512 different glyphs simultaneously.
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.PP
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If the current Unicode value is a control character, or we are
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currently processing an escape sequence, the value will treated
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specially.
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Instead of being turned into a font index and rendered as
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a glyph, it may trigger cursor movement or other control functions.
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See the \fBLinux Console Controls\fP section below for discussion.
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.PP
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It is generally not good practice to hard-wire terminal controls into
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programs.
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Linux supports a
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.BR terminfo (5)
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database of terminal capabilities.
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Rather than emitting console escape sequences by hand, you will almost
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always want to use a terminfo-aware screen library or utility such as
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.BR ncurses (3),
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.BR tput (1),
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or
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.BR reset (1).
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.SS Linux console controls
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This section describes all the control characters and escape sequences
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that invoke special functions (i.e., anything other than writing a
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glyph at the current cursor location) on the Linux console.
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.PP
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.B "Control characters"
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.PP
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A character is a control character if (before transformation
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according to the mapping table) it has one of the 14 codes
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00 (NUL), 07 (BEL), 08 (BS), 09 (HT), 0a (LF), 0b (VT),
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0c (FF), 0d (CR), 0e (SO), 0f (SI), 18 (CAN), 1a (SUB),
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1b (ESC), 7f (DEL).
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One can set a "display control characters" mode (see below),
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and allow 07, 09, 0b, 18, 1a, 7f to be displayed as glyphs.
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On the other hand, in UTF-8 mode all codes 00\(en1f are regarded
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as control characters, regardless of any "display control characters"
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mode.
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.PP
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If we have a control character, it is acted upon immediately
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and then discarded (even in the middle of an escape sequence)
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and the escape sequence continues with the next character.
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(However, ESC starts a new escape sequence, possibly aborting a previous
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unfinished one, and CAN and SUB abort any escape sequence.)
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The recognized control characters are BEL, BS, HT, LF, VT, FF,
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CR, SO, SI, CAN, SUB, ESC, DEL, CSI.
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They do what one would expect:
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.HP
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BEL (0x07, \fB\(haG\fP) beeps;
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.HP
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BS (0x08, \fB\(haH\fP) backspaces one column
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(but not past the beginning of the line);
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.HP
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HT (0x09, \fB\(haI\fP) goes to the next tab stop or to the end of the line
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if there is no earlier tab stop;
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.HP
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LF (0x0A, \fB\(haJ\fP), VT (0x0B, \fB\(haK\fP), and
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FF (0x0C, \fB\(haL\fP) all give a linefeed,
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and if LF/NL (new-line mode) is set also a carriage return;
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.HP
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CR (0x0D, \fB\(haM\fP) gives a carriage return;
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.HP
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SO (0x0E, \fB\(haN\fP) activates the G1 character set;
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.HP
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SI (0x0F, \fB\(haO\fP) activates the G0 character set;
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.HP
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CAN (0x18, \fB\(haX\fP) and SUB (0x1A, \fB\(haZ\fP) abort escape sequences;
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.HP
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ESC (0x1B, \fB\(ha[\fP) starts an escape sequence;
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.HP
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DEL (0x7F) is ignored;
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.HP
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CSI (0x9B) is equivalent to ESC [.
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.PP
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.B "ESC- but not CSI-sequences"
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.ad l
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.TS
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l l lx.
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ESC c RIS Reset.
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ESC D IND Linefeed.
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ESC E NEL Newline.
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ESC H HTS Set tab stop at current column.
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ESC M RI Reverse linefeed.
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ESC Z DECID T{
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DEC private identification. The kernel
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returns the string ESC [ ? 6 c, claiming
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that it is a VT102.
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T}
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ESC 7 DECSC T{
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Save current state (cursor coordinates,
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attributes, character sets pointed at by G0, G1).
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T}
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ESC 8 DECRC T{
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Restore state most recently saved by ESC 7.
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T}
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ESC [ CSI Control sequence introducer
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ESC % Start sequence selecting character set
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ESC % @ \0\0\0Select default (ISO 646 / ISO 8859-1)
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ESC % G \0\0\0Select UTF-8
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ESC % 8 \0\0\0Select UTF-8 (obsolete)
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ESC # 8 DECALN T{
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DEC screen alignment test \- fill screen with E's
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T}
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ESC ( T{
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Start sequence defining G0 character set
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(followed by one of B, 0, U, K, as below)
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T}
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ESC ( B T{
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Select default (ISO 8859-1 mapping)
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T}
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ESC ( 0 T{
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Select VT100 graphics mapping
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T}
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ESC ( U T{
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Select null mapping \- straight to character ROM
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T}
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ESC ( K T{
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Select user mapping \- the map that is loaded by the utility \fBmapscrn\fP(8)
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T}
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ESC ) T{
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Start sequence defining G1 (followed by one of B, 0, U, K, as above).
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T}
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ESC > DECPNM Set numeric keypad mode
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ESC = DECPAM Set application keypad mode
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ESC ] OSC T{
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(Should be: Operating system command)
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ESC ] P \fInrrggbb\fP: set palette, with parameter
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given in 7 hexadecimal digits after the final P :-(.
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Here \fIn\fP is the color (0\(en15), and \fIrrggbb\fP indicates
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the red/green/blue values (0\(en255).
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ESC ] R: reset palette
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T}
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.TE
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.ad
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.PP
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.B "ECMA-48 CSI sequences"
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.PP
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CSI (or ESC [) is followed by a sequence of parameters,
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at most NPAR (16), that are decimal numbers separated by
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semicolons.
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An empty or absent parameter is taken to be 0.
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The sequence of parameters may be preceded by a single question mark.
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.PP
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However, after CSI [ (or ESC [ [) a single character is read
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and this entire sequence is ignored.
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(The idea is to ignore an echoed function key.)
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.PP
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The action of a CSI sequence is determined by its final character.
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.ad l
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.TS
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l l lx.
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@ ICH T{
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Insert the indicated # of blank characters.
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T}
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A CUU T{
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Move cursor up the indicated # of rows.
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T}
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B CUD T{
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Move cursor down the indicated # of rows.
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T}
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C CUF T{
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Move cursor right the indicated # of columns.
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T}
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D CUB T{
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Move cursor left the indicated # of columns.
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T}
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E CNL T{
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Move cursor down the indicated # of rows, to column 1.
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T}
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F CPL T{
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Move cursor up the indicated # of rows, to column 1.
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T}
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G CHA T{
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Move cursor to indicated column in current row.
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T}
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H CUP T{
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Move cursor to the indicated row, column (origin at 1,1).
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T}
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J ED T{
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Erase display (default: from cursor to end of display).
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T}
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T{
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ESC [ 1 J: erase from start to cursor.
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T}
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T{
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ESC [ 2 J: erase whole display.
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T}
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T{
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ESC [ 3 J: erase whole display including scroll-back
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buffer (since Linux 3.0).
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T}
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.\" ESC [ 3 J: commit f8df13e0a901fe55631fed66562369b4dba40f8b
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K EL T{
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Erase line (default: from cursor to end of line).
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T}
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T{
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ESC [ 1 K: erase from start of line to cursor.
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T}
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T{
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ESC [ 2 K: erase whole line.
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T}
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L IL T{
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Insert the indicated # of blank lines.
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T}
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M DL T{
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Delete the indicated # of lines.
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T}
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P DCH T{
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Delete the indicated # of characters on current line.
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T}
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X ECH T{
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Erase the indicated # of characters on current line.
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T}
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a HPR T{
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Move cursor right the indicated # of columns.
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T}
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c DA T{
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Answer ESC [ ? 6 c: "I am a VT102".
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T}
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d VPA T{
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Move cursor to the indicated row, current column.
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T}
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e VPR T{
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Move cursor down the indicated # of rows.
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T}
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f HVP T{
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Move cursor to the indicated row, column.
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T}
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g TBC T{
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Without parameter: clear tab stop at current position.
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T}
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T{
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ESC [ 3 g: delete all tab stops.
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T}
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h SM Set Mode (see below).
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l RM Reset Mode (see below).
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m SGR Set attributes (see below).
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n DSR Status report (see below).
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q DECLL Set keyboard LEDs.
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ESC [ 0 q: clear all LEDs
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ESC [ 1 q: set Scroll Lock LED
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ESC [ 2 q: set Num Lock LED
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ESC [ 3 q: set Caps Lock LED
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r DECSTBM T{
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Set scrolling region; parameters are top and bottom row.
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T}
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s ? Save cursor location.
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u ? Restore cursor location.
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\` HPA T{
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Move cursor to indicated column in current row.
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T}
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.TE
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.ad
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.PP
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.B ECMA-48 Select Graphic Rendition
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.PP
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The ECMA-48 SGR sequence ESC [ \fIparameters\fP m sets display
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attributes.
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Several attributes can be set in the same sequence, separated by
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semicolons.
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An empty parameter (between semicolons or string initiator or
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terminator) is interpreted as a zero.
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.ad l
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.TS
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l lx.
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param result
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0 T{
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reset all attributes to their defaults
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T}
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1 set bold
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2 T{
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set half-bright (simulated with color on a color display)
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T}
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4 T{
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set underscore (simulated with color on a color display)
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(the colors used to simulate dim or underline are set
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using ESC ] ...)
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T}
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5 set blink
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7 set reverse video
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10 T{
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reset selected mapping, display control flag,
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and toggle meta flag (ECMA-48 says "primary font").
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T}
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11 T{
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select null mapping, set display control flag,
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reset toggle meta flag (ECMA-48 says "first alternate font").
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T}
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12 T{
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select null mapping, set display control flag,
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set toggle meta flag (ECMA-48 says "second alternate font").
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The toggle meta flag
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causes the high bit of a byte to be toggled
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before the mapping table translation is done.
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T}
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21 T{
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set underline; before Linux 4.17, this value
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set normal intensity (as is done in many other terminals)
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T}
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22 set normal intensity
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24 underline off
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25 blink off
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27 reverse video off
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30 set black foreground
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31 set red foreground
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32 set green foreground
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33 set brown foreground
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34 set blue foreground
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35 set magenta foreground
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36 set cyan foreground
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37 set white foreground
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38 T{
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256/24-bit foreground color follows, shoehorned into 16 basic colors
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(before Linux 3.16: set underscore on, set default foreground color)
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T}
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39 T{
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set default foreground color
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(before Linux 3.16: set underscore off, set default foreground color)
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T}
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40 set black background
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41 set red background
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42 set green background
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43 set brown background
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44 set blue background
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45 set magenta background
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46 set cyan background
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47 set white background
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48 T{
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256/24-bit background color follows, shoehorned into 8 basic colors
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T}
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49 set default background color
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90..97 T{
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set foreground to bright versions of 30..37
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T}
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100.107 T{
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set background, same as 40..47 (bright not supported)
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T}
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.TE
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.ad
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.PP
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Commands 38 and 48 require further arguments:
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.TS
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l lx.
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;5;x T{
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256 color: values 0..15 are IBGR (black, red, green, ... white),
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16..231 a 6x6x6 color cube, 232..255 a grayscale ramp
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T}
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;2;r;g;b T{
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24-bit color, r/g/b components are in the range 0..255
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T}
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.TE
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.PP
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.B ECMA-48 Mode Switches
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.TP
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ESC [ 3 h
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DECCRM (default off): Display control chars.
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.TP
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ESC [ 4 h
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DECIM (default off): Set insert mode.
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.TP
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ESC [ 20 h
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LF/NL (default off): Automatically follow echo of LF, VT, or FF with CR.
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.\"
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.PP
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.B ECMA-48 Status Report Commands
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.\"
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.TP
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ESC [ 5 n
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Device status report (DSR): Answer is ESC [ 0 n (Terminal OK).
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.TP
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ESC [ 6 n
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Cursor position report (CPR): Answer is ESC [ \fIy\fP ; \fIx\fP R,
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where \fIx,y\fP is the cursor location.
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.\"
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.PP
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.B DEC Private Mode (DECSET/DECRST) sequences
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.PP
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.\"
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These are not described in ECMA-48.
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We list the Set Mode sequences;
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the Reset Mode sequences are obtained by replacing the final \(aqh\(aq
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by \(aql\(aq.
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.TP
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ESC [ ? 1 h
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DECCKM (default off): When set, the cursor keys send an ESC O prefix,
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rather than ESC [.
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.TP
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ESC [ ? 3 h
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DECCOLM (default off = 80 columns): 80/132 col mode switch.
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The driver sources note that this alone does not suffice; some user-mode
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utility such as
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.BR resizecons (8)
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has to change the hardware registers on the console video card.
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.TP
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ESC [ ? 5 h
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DECSCNM (default off): Set reverse-video mode.
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.TP
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ESC [ ? 6 h
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DECOM (default off): When set, cursor addressing is relative to
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the upper left corner of the scrolling region.
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.TP
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ESC [ ? 7 h
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DECAWM (default on): Set autowrap on.
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In this mode, a graphic
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character emitted after column 80 (or column 132 of DECCOLM is on)
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forces a wrap to the beginning of the following line first.
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.TP
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ESC [ ? 8 h
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DECARM (default on): Set keyboard autorepeat on.
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.TP
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ESC [ ? 9 h
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X10 Mouse Reporting (default off): Set reporting mode to 1 (or reset to
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0)\(emsee below.
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.TP
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ESC [ ? 25 h
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DECTECM (default on): Make cursor visible.
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.TP
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ESC [ ? 1000 h
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X11 Mouse Reporting (default off): Set reporting mode to 2 (or reset
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to 0)\(emsee below.
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.\"
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.PP
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.B Linux Console Private CSI Sequences
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.PP
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.\"
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The following sequences are neither ECMA-48 nor native VT102.
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They are native to the Linux console driver.
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Colors are in SGR parameters:
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0 = black, 1 = red, 2 = green, 3 = brown, 4 = blue, 5 = magenta, 6 =
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cyan, 7 = white; 8\(en15 = bright versions of 0\(en7.
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.TS
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l lx.
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ESC [ 1 ; \fIn\fP ] T{
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Set color \fIn\fP as the underline color.
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T}
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ESC [ 2 ; \fIn\fP ] T{
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Set color \fIn\fP as the dim color.
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T}
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ESC [ 8 ] T{
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Make the current color pair the default attributes.
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T}
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ESC [ 9 ; \fIn\fP ] T{
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Set screen blank timeout to \fIn\fP minutes.
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T}
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ESC [ 10 ; \fIn\fP ] T{
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Set bell frequency in Hz.
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T}
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ESC [ 11 ; \fIn\fP ] T{
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Set bell duration in msec.
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T}
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ESC [ 12 ; \fIn\fP ] T{
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Bring specified console to the front.
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T}
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ESC [ 13 ] T{
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Unblank the screen.
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T}
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ESC [ 14 ; \fIn\fP ] T{
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Set the VESA powerdown interval in minutes.
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T}
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ESC [ 15 ] T{
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Bring the previous console to the front
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|
(since Linux 2.6.0).
|
|
T}
|
|
ESC [ 16 ; \fIn\fP ] T{
|
|
Set the cursor blink interval in milliseconds
|
|
(since Linux 4.2).
|
|
T}
|
|
.\" commit bd63364caa8df38bad2b25b11b2a1b849475cce5
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.TE
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.SS Character sets
|
|
The kernel knows about 4 translations of bytes into console-screen
|
|
symbols.
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|
The four tables are: a) Latin1 \-> PC,
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b) VT100 graphics \-> PC, c) PC \-> PC, d) user-defined.
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.PP
|
|
There are two character sets, called G0 and G1, and one of them
|
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is the current character set.
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(Initially G0.)
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Typing \fB\(haN\fP causes G1 to become current,
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\fB\(haO\fP causes G0 to become current.
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.PP
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These variables G0 and G1 point at a translation table, and can be
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changed by the user.
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Initially they point at tables a) and b), respectively.
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The sequences ESC ( B and ESC ( 0 and ESC ( U and ESC ( K cause G0 to
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point at translation table a), b), c), and d), respectively.
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The sequences ESC ) B and ESC ) 0 and ESC ) U and ESC ) K cause G1 to
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point at translation table a), b), c), and d), respectively.
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.PP
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The sequence ESC c causes a terminal reset, which is what you want if the
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screen is all garbled.
|
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The oft-advised "echo \(haV\(haO" will make only G0 current,
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but there is no guarantee that G0 points at table a).
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In some distributions there is a program
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.BR reset (1)
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that just does "echo \(ha[c".
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If your terminfo entry for the console is correct
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(and has an entry rs1=\eEc), then "tput reset" will also work.
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.PP
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The user-defined mapping table can be set using
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.BR mapscrn (8).
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|
The result of the mapping is that if a symbol c is printed, the symbol
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s = map[c] is sent to the video memory.
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The bitmap that corresponds to
|
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s is found in the character ROM, and can be changed using
|
|
.BR setfont (8).
|
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.SS Mouse tracking
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The mouse tracking facility is intended to return
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.BR xterm (1)-compatible
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mouse status reports.
|
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Because the console driver has no way to know
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the device or type of the mouse, these reports are returned in the
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console input stream only when the virtual terminal driver receives
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a mouse update ioctl.
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These ioctls must be generated by a mouse-aware
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user-mode application such as the
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.BR gpm (8)
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daemon.
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.PP
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The mouse tracking escape sequences generated by
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\fBxterm\fP(1) encode numeric parameters in a single character as
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\fIvalue\fP+040.
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For example, \(aq!\(aq is 1.
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The screen coordinate system is 1-based.
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.PP
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The X10 compatibility mode sends an escape sequence on button press
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encoding the location and the mouse button pressed.
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It is enabled by sending ESC [ ? 9 h and disabled with ESC [ ? 9 l.
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On button press, \fBxterm\fP(1) sends
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ESC [ M \fIbxy\fP (6 characters).
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Here \fIb\fP is button\-1,
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and \fIx\fP and \fIy\fP are the x and y coordinates of the mouse
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when the button was pressed.
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This is the same code the kernel also produces.
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.PP
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Normal tracking mode (not implemented in Linux 2.0.24) sends an escape
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sequence on both button press and release.
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Modifier information is also sent.
|
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It is enabled by sending ESC [ ? 1000 h and disabled with
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ESC [ ? 1000 l.
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On button press or release, \fBxterm\fP(1) sends ESC [ M
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\fIbxy\fP.
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The low two bits of \fIb\fP encode button information:
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|
0=MB1 pressed, 1=MB2 pressed, 2=MB3 pressed, 3=release.
|
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The upper bits encode what modifiers were down when the button was
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pressed and are added together: 4=Shift, 8=Meta, 16=Control.
|
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Again \fIx\fP and
|
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\fIy\fP are the x and y coordinates of the mouse event.
|
|
The upper left corner is (1,1).
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|
.SS Comparisons with other terminals
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Many different terminal types are described, like the Linux console,
|
|
as being "VT100-compatible".
|
|
Here we discuss differences between the
|
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Linux console and the two most important others, the DEC VT102 and
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.BR xterm (1).
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|
.\"
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.PP
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.B Control-character handling
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.PP
|
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The VT102 also recognized the following control characters:
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|
.HP
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NUL (0x00) was ignored;
|
|
.HP
|
|
ENQ (0x05) triggered an answerback message;
|
|
.HP
|
|
DC1 (0x11, \fB\(haQ\fP, XON) resumed transmission;
|
|
.HP
|
|
DC3 (0x13, \fB\(haS\fP, XOFF) caused VT100 to ignore (and stop transmitting)
|
|
all codes except XOFF and XON.
|
|
.PP
|
|
VT100-like DC1/DC3 processing may be enabled by the terminal driver.
|
|
.PP
|
|
The
|
|
.BR xterm (1)
|
|
program (in VT100 mode) recognizes the control characters
|
|
BEL, BS, HT, LF, VT, FF, CR, SO, SI, ESC.
|
|
.\"
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.PP
|
|
.B Escape sequences
|
|
.PP
|
|
VT100 console sequences not implemented on the Linux console:
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|
.TS
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l l l.
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ESC N SS2 T{
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|
Single shift 2. (Select G2 character set for the next character only.)
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T}
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|
ESC O SS3 T{
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|
Single shift 3. (Select G3 character set for the next character only.)
|
|
T}
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|
ESC P DCS T{
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|
Device control string (ended by ESC \e)
|
|
T}
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|
ESC X SOS Start of string.
|
|
ESC \(ha PM Privacy message (ended by ESC \e)
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|
ESC \e ST String terminator
|
|
ESC * ... Designate G2 character set
|
|
ESC + ... Designate G3 character set
|
|
.TE
|
|
.PP
|
|
The program
|
|
.BR xterm (1)
|
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(in VT100 mode) recognizes ESC c, ESC # 8, ESC >, ESC =,
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|
ESC D, ESC E, ESC H, ESC M, ESC N, ESC O, ESC P ... ESC \e,
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|
ESC Z (it answers ESC [ ? 1 ; 2 c, "I am a VT100 with
|
|
advanced video option")
|
|
and ESC \(ha ... ESC \e 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 US-ASCII,
|
|
respectively.
|
|
.PP
|
|
The user can configure \fBxterm\fP(1) to respond to VT220-specific
|
|
control sequences, and it will identify itself as a VT52, VT100, and
|
|
up depending on the way it is configured and initialized.
|
|
.PP
|
|
It accepts ESC ] (OSC) for the setting of certain resources.
|
|
In addition to the ECMA-48 string terminator (ST),
|
|
\fBxterm\fP(1) accepts a BEL to terminate an OSC string.
|
|
These are a few of the OSC control sequences recognized by \fBxterm\fP(1):
|
|
.TS
|
|
l l.
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|
ESC ] 0 ; \fItxt\fP ST T{
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Set icon name and window title to \fItxt\fP.
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T}
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ESC ] 1 ; \fItxt\fP ST Set icon name to \fItxt\fP.
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ESC ] 2 ; \fItxt\fP ST Set window title to \fItxt\fP.
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ESC ] 4 ; \fInum\fP; \fItxt\fP ST Set ANSI color \fInum\fP to \fItxt\fP.
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ESC ] 10 ; \fItxt\fP ST Set dynamic text color to \fItxt\fP.
|
|
ESC ] 4 6 ; \fIname\fP ST T{
|
|
Change log file to \fIname\fP (normally disabled by a compile-time option).
|
|
T}
|
|
ESC ] 5 0 ; \fIfn\fP ST Set font to \fIfn\fP.
|
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.TE
|
|
.PP
|
|
It recognizes the following with slightly modified meaning
|
|
(saving more state, behaving closer to VT100/VT220):
|
|
.TS
|
|
l l l.
|
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ESC 7 DECSC Save cursor
|
|
ESC 8 DECRC Restore cursor
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|
.TE
|
|
.PP
|
|
It also recognizes
|
|
.TS
|
|
l l lx.
|
|
ESC F T{
|
|
Cursor to lower left corner of screen (if enabled
|
|
by \fBxterm\fP(1)'s \fBhpLowerleftBugCompat\fP resource)
|
|
T}
|
|
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.
|
|
ESC } LS2R Invoke the G2 character set as GR.
|
|
ESC \(ti LS1R Invoke the G1 character set as GR.
|
|
.TE
|
|
.PP
|
|
It also recognizes ESC % and provides a more complete UTF-8
|
|
implementation than Linux console.
|
|
.\"
|
|
.PP
|
|
.B CSI Sequences
|
|
.PP
|
|
Old versions of \fBxterm\fP(1), for example, from X11R5,
|
|
interpret the blink SGR as a bold SGR.
|
|
Later versions which implemented ANSI colors, for example,
|
|
XFree86 3.1.2A in 1995, improved this by allowing
|
|
the blink attribute to be displayed as a color.
|
|
Modern versions of xterm implement blink SGR as blinking text
|
|
and still allow colored text as an alternate rendering of SGRs.
|
|
Stock X11R6 versions did not recognize the color-setting SGRs until
|
|
the X11R6.8 release, which incorporated XFree86 xterm.
|
|
All ECMA-48 CSI sequences recognized by Linux are also recognized by
|
|
.IR xterm ,
|
|
however \fBxterm\fP(1) implements several ECMA-48 and DEC control sequences
|
|
not recognized by Linux.
|
|
.PP
|
|
The \fBxterm\fP(1)
|
|
program recognizes all of the DEC Private Mode sequences listed
|
|
above, but none of the Linux private-mode sequences.
|
|
For discussion of \fBxterm\fP(1)'s
|
|
own private-mode sequences, refer to the
|
|
\fIXterm Control Sequences\fP
|
|
document by
|
|
Edward Moy,
|
|
Stephen Gildea,
|
|
and Thomas E.\& Dickey
|
|
available with the X distribution.
|
|
That document, though terse, is much longer than this manual page.
|
|
For a chronological overview,
|
|
.PP
|
|
.RS
|
|
.UR http://invisible\-island.net\:/xterm\:/xterm.log.html
|
|
.UE
|
|
.RE
|
|
.PP
|
|
details changes to xterm.
|
|
.PP
|
|
The \fIvttest\fP program
|
|
.PP
|
|
.RS
|
|
.UR http://invisible\-island.net\:/vttest/
|
|
.UE
|
|
.RE
|
|
.PP
|
|
demonstrates many of these control sequences.
|
|
The \fBxterm\fP(1) source distribution also contains sample
|
|
scripts which exercise other features.
|
|
.SH NOTES
|
|
ESC 8 (DECRC) is not able to restore the character set changed with
|
|
ESC %.
|
|
.SH BUGS
|
|
In 2.0.23, CSI is broken, and NUL is not ignored inside
|
|
escape sequences.
|
|
.PP
|
|
Some older kernel versions (after 2.0) interpret 8-bit control
|
|
sequences.
|
|
These "C1 controls" use codes between 128 and 159 to replace
|
|
ESC [, ESC ] and similar two-byte control sequence initiators.
|
|
There are fragments of that in modern kernels (either overlooked or
|
|
broken by changes to support UTF-8),
|
|
but the implementation is incomplete and should be regarded
|
|
as unreliable.
|
|
.PP
|
|
Linux "private mode" sequences do not follow the rules in ECMA-48
|
|
for private mode control sequences.
|
|
In particular, those ending with ] do not use a standard terminating
|
|
character.
|
|
The OSC (set palette) sequence is a greater problem,
|
|
since \fBxterm\fP(1) may interpret this as a control sequence
|
|
which requires a string terminator (ST).
|
|
Unlike the \fBsetterm\fP(1) sequences which will be ignored (since
|
|
they are invalid control sequences), the palette sequence will make
|
|
\fBxterm\fP(1) appear to hang (though pressing the return-key
|
|
will fix that).
|
|
To accommodate applications which have been hardcoded to use Linux
|
|
control sequences,
|
|
set the \fBxterm\fP(1) resource \fBbrokenLinuxOSC\fP to true.
|
|
.PP
|
|
An older version of this document implied that Linux recognizes the
|
|
ECMA-48 control sequence for invisible text.
|
|
It is ignored.
|
|
.SH SEE ALSO
|
|
.BR ioctl_console (2),
|
|
.BR charsets (7)
|