Supported Terminal Sequences

Bell

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

Backspace

By default it is not possible to move the cursor past the leftmost position. If reverse wrap-around (CSI ? 45 h) is set, a previous soft line wrap (DECAWM) can be undone with BS within the scroll margins. In that case the cursor will wrap back to the end of the previous row. Note that it is not possible to peek back into the scrollbuffer with the cursor, thus at the home position (top-leftmost cell) this has no effect.

Line Feed

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

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:

Erase In Line

Supported param values:

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:

DEC Private Set Mode

Supported param values by DECSET:

Reset Mode

Supported param values by RM:

DEC Private Reset Mode

Supported param values by DECRST:

Select Graphic Rendition

SGR selects one or more character attributes at the same time. Multiple params (up to 32) are applied 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:

Underline supports subparams to denote the style in the form 4 : x:

Extended colors are supported for foreground (Ps=38), background (Ps=48) and underline (Ps=58) as follows:

Request Mode

Returns a report as CSI Ps; Pm $ y (DECRPM), where Ps is the mode number as in SM/RM or DECSET/DECRST, and Pm is the mode value:

• 0: not recognized
• 1: set
• 2: reset
• 3: permanently set
• 4: permanently reset

For modes not understood xterm.js always returns notRecognized. In general this means, that a certain operation mode is not implemented and cannot be used.

Modes changing the active terminal buffer (47, 1047, 1049) are not subqueried and only report, whether the alternate buffer is set.

Mouse encodings and mouse protocols are handled mutual exclusive, thus only one of each of those can be set at a given time.

There is a chance, that some mode reports are not fully in line with xterm.js’ behavior, e.g. if the default implementation already exposes a certain behavior. If you find discrepancies in the mode reports, please file a bug.

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:

• IRM is reset (dafault = false)
• scroll margins are reset (default = viewport size)
• erase attributes are reset to default
• charsets are reset
• DECSC data is reset to initial values
• DECOM is reset to absolute mode

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.

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:

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.

Set ANSI color

c is the color index between 0 and 255. The color format of spec is derived from XParseColor (see OSC 10 for supported formats). There may be multipe c ; spec pairs present in the same instruction. If spec contains ? the terminal returns a sequence with the currently set color.

Create hyperlink

uri is a hyperlink starting with http://, https://, ftp://, file:// or mailto://. params is an optional list of key=value assignments, separated by the : character. Example: id=xyz123:foo=bar:baz=quux. Currently only the id key is defined. Cells that share the same ID and URI share hover feedback. Use OSC 8 ; ; BEL to finish the current hyperlink.

Set or query default foreground color

To set the color, the following color specification formats are supported:

• rgb:<red>/<green>/<blue> for <red>, <green>, <blue> in h | hh | hhh | hhhh, where h is a single hexadecimal digit (case insignificant). The different widths scale from 4 bit (h) to 16 bit (hhhh) and get converted to 8 bit (hh).
• #RGB - 4 bits per channel, expanded to #R0G0B0
• #RRGGBB - 8 bits per channel
• #RRRGGGBBB - 12 bits per channel, truncated to #RRGGBB
• #RRRRGGGGBBBB - 16 bits per channel, truncated to #RRGGBB

Note: X11 named colors are currently unsupported.

If Pt contains ? instead of a color specification, the terminal returns a sequence with the current default foreground color (use that sequence to restore the color after changes).

Note: Other than xterm, xterm.js does not support OSC 12 - 19. Therefore stacking multiple Pt separated by ; only works for the first two entries.

Reset ANSI color

c is the color index between 0 and 255. This function restores the default color for c as specified by the loaded theme. Any number of c parameters may be given. If no parameters are given, the entire indexed color table will be reset.