VT features

NOTE: WORK IN PROGRESS

xterm.js version: 4.3.0

Table of Contents

• General notes
• C0
• C1
• CSI
• DCS
• ESC
• OSC

General notes

This document lists xterm.js' support of terminal sequences. The sequences are grouped by their sequence type:

• C0: single byte command (7bit control codes, byte range \x00 .. \x1F, \x7F)
• C1: single byte command (8bit control codes, byte range \x80 .. \x9F)
• ESC: sequence starting with ESC (\x1B)
• CSI - Control Sequence Introducer: sequence starting with ESC [ (7bit) or CSI (\x9B, 8bit)
• DCS - Device Control String: sequence starting with ESC P (7bit) or DCS (\x90, 8bit)
• OSC - Operating System Command: sequence starting with ESC ] (7bit) or OSC (\x9D, 8bit)

Application Program Command (APC), Privacy Message (PM) and Start of String (SOS) are recognized but not supported, any sequence of these types will be ignored. They are also not hookable by the API.

Note that the list only contains sequences implemented in xterm.js' core codebase. Missing sequences are either not supported or unstable/experimental. Furthermore addons or integrations can provide additional custom sequences.

To denote the sequences the tables use the same abbreviations as xterm does:

• Ps: A single (usually optional) numeric parameter, composed of one or more decimal digits.
• Pm: A multiple numeric parameter composed of any number of single numeric parameters, separated by ; character(s), e.g. Ps ; Ps ; ....
• Pt: A text parameter composed of printable characters. Note that for most commands with Pt only ASCII printables are specified to work. Additionally the parser will let pass any codepoint greater than C1 as printable.

C0

Mnemonic	Name	Sequence	Short Description	Support
NUL	Null	\0, \x00	NUL is ignored.	✓
BEL	Bell	\a, \x07	Ring the bell. more	✓
BS	Backspace	\b, \x08	Move the cursor one position to the left.	✓
HT	Horizontal Tabulation	\t, \x09	Move the cursor to the next character tab stop.	✓
LF	Line Feed	\n, \x0A	Move the cursor one row down, scrolling if needed. more	✓
VT	Vertical Tabulation	\v, \x0B	Treated as LF.	✓
FF	Form Feed	\f, \x0C	Treated as LF.	✓
CR	Carriage Return	\r, \x0D	Move the cursor to the beginning of the row.	✓
SO	Shift Out	\x0E	Switch to an alternative character set.	Partial
SI	Shift In	\x0F	Return to regular character set after Shift Out.	✓
ESC	Escape	\e, \x1B	Start of a sequence. Cancels any other sequence.	✓

Bell

The behavior of the bell is further customizable with ITerminalOptions.bellStyle and ITerminalOptions.bellSound.

Line Feed

Scrolling is restricted to scroll margins and will only happen on the bottom line.

C1

Mnemonic	Name	Sequence	Short Description	Support
IND	Index	\x84	Move the cursor one line down scrolling if needed.	✓
NEL	Next Line	\x85	Move the cursor to the beginning of the next row.	✓
HTS	Horizontal Tabulation Set	\x88	Places a tab stop at the current cursor position.	✓
DCS	Device Control String	\x90	Start of a DCS sequence.	✓
CSI	Control Sequence Introducer	\x9B	Start of a CSI sequence.	✓
ST	String Terminator	\x9C	Terminator used for string type sequences.	✓
OSC	Operating System Command	\x9D	Start of an OSC sequence.	✓
PM	Privacy Message	\x9E	Start of a privacy message.	✓
APC	Application Program Command	\x9F	Start of an APC sequence.	✓

CSI

Mnemonic	Name	Sequence	Short Description	Support
ICH	Insert Characters	CSI Ps @	Insert Ps (blank) characters (default = 1). more	✓
SL	Scroll Left	CSI Ps SP @	Scroll viewport Ps times to the left. more	✓
CUU	Cursor Up	CSI Ps A	Move cursor Ps times up (default=1). more	✓
SR	Scroll Right	CSI Ps SP A	Scroll viewport Ps times to the right. more	✓
CUD	Cursor Down	CSI Ps B	Move cursor Ps times down (default=1). more	✓
CUF	Cursor Forward	CSI Ps C	Move cursor Ps times forward (default=1).	✓
CUB	Cursor Backward	CSI Ps D	Move cursor Ps times backward (default=1).	✓
CNL	Cursor Next Line	CSI Ps E	Move cursor Ps times down (default=1) and to the first column. more	✓
CPL	Cursor Backward	CSI Ps F	Move cursor Ps times up (default=1) and to the first column. more	✓
CHA	Cursor Horizontal Absolute	CSI Ps G	Move cursor to Ps-th column of the active row (default=1).	✓
CUP	Cursor Position	CSI Ps ; Ps H	Set cursor to position [Ps, Ps] (default = [1, 1]). more	✓
CHT	Cursor Horizontal Tabulation	CSI Ps I	Move cursor Ps times tabs forward (default=1).	✓
DECSED	Selective Erase In Display	CSI ? Ps J	Currently the same as ED.	Partial
ED	Erase In Display	CSI Ps J	Erase various parts of the viewport. more	✓
DECSEL	Selective Erase In Line	CSI ? Ps K	Currently the same as EL.	Partial
EL	Erase In Line	CSI Ps K	Erase various parts of the active row. more	✓
IL	Insert Line	CSI Ps L	Insert Ps blank lines at active row (default=1). more	✓
DL	Delete Line	CSI Ps M	Delete Ps lines at active row (default=1). more	✓
DCH	Delete Character	CSI Ps P	Delete Ps characters (default=1). more	✓
SU	Scroll Up	CSI Ps S	Scroll Ps lines up (default=1).	✓
SD	Scroll Down	CSI Ps T	Scroll Ps lines down (default=1).	✓
ECH	Erase Character	CSI Ps X	Erase Ps characters from current cursor position to the right (default=1). more	✓
CBT	Cursor Backward Tabulation	CSI Ps Z	Move cursor Ps tabs backward (default=1).	✓
HPA	Horizontal Position Absolute	CSI Ps `	Same as CHA.	✓
HPR	Horizontal Position Relative	CSI Ps a	Same as CUF.	✓
REP	Repeat Preceding Character	CSI Ps b	Repeat preceding character Ps times (default=1). more	✓
DA1	Primary Device Attributes	CSI c	Send primary device attributes.	✓
DA2	Secondary Device Attributes	CSI > c	Send primary device attributes.	✓
VPA	Vertical Position Absolute	CSI Ps d	Move cursor to Ps-th row (default=1).	✓
VPR	Vertical Position Relative	CSI Ps e	Move cursor Ps times down (default=1).	✓
HVP	Horizontal and Vertical Position	CSI Ps ; Ps f	Same as CUP.	✓
TBC	Tab Clear	CSI Ps g	Clear tab stops at current position (0) or all (3) (default=0). more	✓
SM	Set Mode	CSI Pm h	Set various terminal modes. more	Partial
DECSET	DEC Private Set Mode	CSI ? Pm h	Set various terminal attributes. more	Partial
RM	Reset Mode	CSI Pm l	Set various terminal attributes. more	Partial
DECRST	DEC Private Reset Mode	CSI ? Pm l	Reset various terminal attributes. more	Partial
SGR	Select Graphic Rendition	CSI Pm m	Set/Reset various text attributes. more	Partial
DSR	Device Status Report	CSI Ps n	Request cursor position (CPR) with Ps = 6.	✓
DECDSR	DEC Device Status Report	CSI ? Ps n	Only CPR is supported (same as DSR).	Partial
DECSTR	Soft Terminal Reset	CSI ! p	Reset several terminal attributes to initial state. more	✓
DECSCUSR	Set Cursor Style	CSI Ps SP q	Set cursor style. more	✓
DECSTBM	Set Top and Bottom Margin	CSI Ps ; Ps r	Set top and bottom margins of the viewport [top;bottom] (default = viewport size).	✓
SCOSC	Save Cursor	CSI s	Save cursor position, charmap and text attributes.	Partial
SCORC	Restore Cursor	CSI u	Restore cursor position, charmap and text attributes.	Partial
DECIC	Insert Columns	CSI Ps ' }	Insert Ps columns at cursor position. more	✓
DECDC	Delete Columns	CSI Ps ' ~	Delete Ps columns at cursor position. more	✓

Insert Characters

The ICH sequence inserts Ps blank characters. The cursor remains at the beginning of the blank characters. Text between the cursor and right margin moves to the right. Characters moved past the right margin are lost.

Scroll Left

SL moves the content of all lines within the scroll margins Ps times to the left. SL has no effect outside of the scroll margins.

Cursor Up

If the cursor would pass the top scroll margin, it will stop there.

Scroll Right

SL moves the content of all lines within the scroll margins Ps times to the right. Content at the right margin is lost. SL has no effect outside of the scroll margins.

Cursor Down

If the cursor would pass the bottom scroll margin, it will stop there.

Cursor Next Line

Same as CUD, additionally places the cursor at the first column.

Cursor Backward

Same as CUU, additionally places the cursor at the first column.

Cursor Position

If ORIGIN mode is set, places the cursor to the absolute position within the scroll margins. If ORIGIN mode is not set, places the cursor to the absolute position within the viewport. Note that the coordinates are 1-based, thus the top left position starts at 1 ; 1.

Erase In Display

Supported param values:

Ps	Effect
0	Erase from the cursor through the end of the viewport.
1	Erase from the beginning of the viewport through the cursor.
2	Erase complete viewport.
3	Erase scrollback.

Erase In Line

Supported param values:

Ps	Effect
0	Erase from the cursor through the end of the row.
1	Erase from the beginning of the line through the cursor.
2	Erase complete line.

Insert Line

For every inserted line at the scroll top one line at the scroll bottom gets removed. The cursor is set to the first column. IL has no effect if the cursor is outside the scroll margins.

Delete Line

For every deleted line at the scroll top one blank line at the scroll bottom gets appended. The cursor is set to the first column. DL has no effect if the cursor is outside the scroll margins.

Delete Character

As characters are deleted, the remaining characters between the cursor and right margin move to the left. Character attributes move with the characters. The terminal adds blank characters at the right margin.

Erase Character

ED erases Ps characters from current cursor position to the right. ED works inside or outside the scrolling margins.

Repeat Preceding Character

REP repeats the previous character Ps times advancing the cursor, also wrapping if DECAWM is set. REP has no effect if the sequence does not follow a printable ASCII character (NOOP for any other sequence in between or NON ASCII characters).

Tab Clear

Clearing tabstops off the active row (Ps = 2, VT100) is currently not supported.

Set Mode

Supported param values by SM:

Param	Action	Support
2	Keyboard Action Mode (KAM). Always on.	✗
4	Insert Mode (IRM).	✓
12	Send/receive (SRM). Always off.	✗
20	Automatic Newline (LNM). Always off.	✗

DEC Private Set Mode

Supported param values by DECSET:

param	Action	Support
1	Application Cursor Keys (DECCKM).	✓
2	Designate US-ASCII for character sets G0-G3 (DECANM).	✓
3	132 Column Mode (DECCOLM).	✓
6	Origin Mode (DECOM).	✓
7	Auto-wrap Mode (DECAWM).	✓
8	Auto-repeat Keys (DECARM). Always on.	✗
9	X10 xterm mouse protocol.	✓
12	Start Blinking Cursor.	✓
25	Show Cursor (DECTCEM).	✓
47	Use Alternate Screen Buffer.	✓
66	Application keypad (DECNKM).	✓
1000	X11 xterm mouse protocol.	✓
1002	Use Cell Motion Mouse Tracking.	✓
1003	Use All Motion Mouse Tracking.	✓
1004	Send FocusIn/FocusOut events	✓
1005	Enable UTF-8 Mouse Mode.	✗
1006	Enable SGR Mouse Mode.	✓
1015	Enable urxvt Mouse Mode.	✗
1047	Use Alternate Screen Buffer.	✓
1048	Save cursor as in DECSC.	✓
1049	Save cursor and switch to alternate buffer clearing it.	Partial
2004	Set bracketed paste mode.	✓

Reset Mode

Supported param values by RM:

Param	Action	Support
2	Keyboard Action Mode (KAM). Always on.	✗
4	Replace Mode (IRM). (default)	✓
12	Send/receive (SRM). Always off.	✗
20	Normal Linefeed (LNM). Always off.	✗

DEC Private Reset Mode

Supported param values by DECRST:

param	Action	Support
1	Normal Cursor Keys (DECCKM).	✓
2	Designate VT52 mode (DECANM).	✗
3	80 Column Mode (DECCOLM).	Broken
6	Normal Cursor Mode (DECOM).	✓
7	No Wraparound Mode (DECAWM).	✓
8	No Auto-repeat Keys (DECARM).	✗
9	Don't send Mouse X & Y on button press.	✓
12	Stop Blinking Cursor.	✓
25	Hide Cursor (DECTCEM).	✓
47	Use Normal Screen Buffer.	✓
66	Numeric keypad (DECNKM).	✓
1000	Don't send Mouse reports.	✓
1002	Don't use Cell Motion Mouse Tracking.	✓
1003	Don't use All Motion Mouse Tracking.	✓
1004	Don't send FocusIn/FocusOut events.	✓
1005	Disable UTF-8 Mouse Mode.	✗
1006	Disable SGR Mouse Mode.	✓
1015	Disable urxvt Mouse Mode.	✗
1047	Use Normal Screen Buffer (clearing screen if in alt).	✓
1048	Restore cursor as in DECRC.	✓
1049	Use Normal Screen Buffer and restore cursor.	✓
2004	Reset bracketed paste mode.	✓

Select Graphic Rendition

SGR selects one or more character attributes at the same time. Multiple params (up to 32) are applied from in order from left to right. The changed attributes are applied to all new characters received. If you move characters in the viewport by scrolling or any other means, then the attributes move with the characters.

Supported param values by SGR:

Param	Meaning	Support
0	Normal (default). Resets any other preceding SGR.	✓
1	Bold. (also see options.drawBoldTextInBrightColors)	✓
2	Faint, decreased intensity.	✓
3	Italic.	✓
4	Underlined. (no support for newer underline styles)	✓
5	Slowly blinking.	✗
6	Rapidly blinking.	✗
7	Inverse. Flips foreground and background color.	✓
8	Invisible (hidden).	✓
9	Crossed-out characters.	✗
21	Doubly underlined.	✗
22	Normal (neither bold nor faint).	✓
23	No italic.	✓
24	Not underlined.	✓
25	Steady (not blinking).	✓
27	Positive (not inverse).	✓
28	Visible (not hidden).	✓
29	Not Crossed-out.	✗
30	Foreground color: Black.	✓
31	Foreground color: Red.	✓
32	Foreground color: Green.	✓
33	Foreground color: Yellow.	✓
34	Foreground color: Blue.	✓
35	Foreground color: Magenta.	✓
36	Foreground color: Cyan.	✓
37	Foreground color: White.	✓
38	Foreground color: Extended color.	Partial
39	Foreground color: Default (original).	✓
40	Background color: Black.	✓
41	Background color: Red.	✓
42	Background color: Green.	✓
43	Background color: Yellow.	✓
44	Background color: Blue.	✓
45	Background color: Magenta.	✓
46	Background color: Cyan.	✓
47	Background color: White.	✓
48	Background color: Extended color.	Partial
49	Background color: Default (original).	✓
90 - 97	Bright foreground color (analogous to 30 - 37).	✓
100 - 107	Bright background color (analogous to 40 - 47).	✓

Extended colors are supported for foreground (Ps=38) and background (Ps=48) as follows:

Ps + 1	Meaning	Support
0	Implementation defined.	✗
1	Transparent.	✗
2	RGB color as Ps ; 2 ; R ; G ; B or Ps : 2 : : R : G : B.	✓
3	CMY color.	✗
4	CMYK color.	✗
5	Indexed (256 colors) as Ps ; 5 ; INDEX or Ps : 5 : INDEX.	✓

Soft Terminal Reset

There are two terminal reset sequences - RIS and DECSTR. While RIS performs almost a full terminal bootstrap, DECSTR only resets certain attributes. For most needs DECSTR should be sufficient.

The following terminal attributes are reset to default values:

• cursor is reset (default = visible, home position)
• IRM is reset (dafault = false)
• scroll margins are reset (default = viewport size)
• erase attributes are reset to default
• charsets are reset

Set Cursor Style

Supported cursor styles:

• empty, 0 or 1: steady block
• 2: blink block
• 3: steady underline
• 4: blink underline
• 5: steady bar
• 6: blink bar

Insert Columns

DECIC inserts Ps times blank columns at the cursor position for all lines with the scroll margins, moving content to the right. Content at the right margin is lost. DECIC has no effect outside the scrolling margins.

Delete Columns

DECDC deletes Ps times columns at the cursor position for all lines with the scroll margins, moving content to the left. Blank columns are added at the right margin. DECDC has no effect outside the scrolling margins.

DCS

Mnemonic	Name	Sequence	Short Description	Support
DECRQSS	Request Selection or Setting	DCS $ q Pt ST	Request several terminal settings. more	Partial
DECUDK	User Defined Keys	`DCS Ps ; Ps	Pt ST`	Definitions for user-defined keys.
SIXEL	SIXEL Graphics	DCS Ps ; Ps ; Ps ; q Pt ST	Draw SIXEL image starting at cursor position.	✗
XTGETTCAP	Request Terminfo String	DCS + q Pt ST	Request Terminfo String.	✗
XTSETTCAP	Set Terminfo Data	DCS + p Pt ST	Set Terminfo Data.	✗

Request Selection or Setting

Response is in the form ESC P 1 $ r Pt ST for valid requests, where Pt contains the corresponding CSI string, ESC P 0 ST for invalid requests.

Supported requests and responses:

Type	Request	Response (Pt)
Graphic Rendition (SGR)	DCS $ q m ST	always reporting 0m (currently broken)
Top and Bottom Margins (DECSTBM)	DCS $ q r ST	Ps ; Ps r
Cursor Style (DECSCUSR)	DCS $ q SP q ST	Ps SP q
Protection Attribute (DECSCA)	DCS $ q " q ST	always reporting 0 " q (DECSCA is unsupported)
Conformance Level (DECSCL)	DCS $ q " p ST	always reporting 61 ; 1 " p (DECSCL is unsupported)

ESC

Mnemonic	Name	Sequence	Short Description	Support
SC	Save Cursor	ESC 7	Save cursor position, charmap and text attributes.	✓
DECALN	Screen Alignment Pattern	ESC # 8	Fill viewport with a test pattern (E).	✓
RC	Restore Cursor	ESC 8	Restore cursor position, charmap and text attributes.	✓
IND	Index	ESC D	Move the cursor one line down scrolling if needed.	✓
NEL	Next Line	ESC E	Move the cursor to the beginning of the next row.	✓
HTS	Horizontal Tabulation Set	ESC H	Places a tab stop at the current cursor position.	✓
IR	Reverse Index	ESC M	Move the cursor one line up scrolling if needed.	✓
DCS	Device Control String	ESC P	Start of a DCS sequence.	✓
CSI	Control Sequence Introducer	ESC [	Start of a CSI sequence.	✓
ST	String Terminator	ESC \	Terminator used for string type sequences.	✓
OSC	Operating System Command	ESC ]	Start of an OSC sequence.	✓
PM	Privacy Message	ESC ^	Start of a privacy message.	✓
APC	Application Program Command	ESC _	Start of an APC sequence.	✓

OSC

Note: Other than listed in the table, the parser recognizes both ST (ECMA-48) and BEL (xterm) as OSC sequence finalizer.

Identifier	Sequence	Short Description	Support
0	OSC 0 ; Pt BEL	Set window title and icon name. more	Partial
1	OSC 1 ; Pt BEL	Set icon name.	✗
2	OSC 2 ; Pt BEL	Set window title. more	✓

Set Windows Title and Icon Name

Icon name is not supported. For Window Title see below.

Set Windows Title

xterm.js does not manipulate the title directly, instead exposes changes via the event Terminal.onTitleChange.