OSC 10

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Experimental

OSC 10 sets or queries the terminal's default foreground (text) color. This is the color used for text that has not been explicitly colored with SGR attributes.

Syntax

OSC 10 ; spec ST      Set default foreground color
OSC 10 ; ? ST         Query current foreground color

Formal syntax

OSC10_set   = 0x1b, "]", "10", ";", color_spec, ( 0x07 | 0x1b, "\\" ) ;
OSC10_query = 0x1b, "]", "10", ";", "?", ( 0x07 | 0x1b, "\\" ) ;
color_spec  = "rgb:", hex, "/", hex, "/", hex ;
hex         = hex_digit, hex_digit, [ hex_digit, hex_digit ] ;
hex_digit   = digit | "a" | "b" | "c" | "d" | "e" | "f"
          | "A" | "B" | "C" | "D" | "E" | "F" ;
digit       = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" ;

Parameters

Parameter	Description	Default
`spec`	Color specification in X11 format (e.g., `rgb:RR/GG/BB`) or `?` to query	(required)

Response

When queried with ?, the terminal responds with the current foreground color:

OSC 10 ; rgb:RRRR/GGGG/BBBB ST

The response uses 16-bit color components (four hex digits per channel).

Description

Per the XTerm control sequences documentation, OSC 10 controls the VT100 text foreground color, also known as the "dynamic color" for the default foreground. The color specification uses the same X11 color syntax as OSC 4, most commonly rgb:RR/GG/BB.

The query form (OSC 10 ; ?) is commonly used by applications to detect the terminal's current color scheme. By querying both OSC 10 (foreground) and OSC 11 (background), an application can determine whether the terminal is using a light or dark theme and adapt its output accordingly.

Changes made with OSC 10 take effect immediately and affect all text rendered with the default foreground color. Text that has been explicitly colored with SGR sequences is not affected.

Examples

# Set foreground to white
printf '\e]10;rgb:ff/ff/ff\e\\'

# Set foreground to a light gray
printf '\e]10;rgb:cc/cc/cc\a'

# Query current foreground color
printf '\e]10;?\e\\'

# Detect dark/light theme by querying background color
# (parse the response to determine brightness)
printf '\e]10;?\a'

Specifications

Specification	Section
XTerm ctlseqs	—

Terminal support

Terminal	Support	Version	Notes
Terminal Emulators
Alacritty	✓	Yes	Listed as IMPLEMENTED in escape_support.md:100
Bobcat	?	?	DynamicColors() enabled from v0.9.0, but actual OSC 10/11/12 handling is in TerminalCtrl library
contour	✓	v0.1.0	Set/query default foreground color
foot	✓	Yes	Query/set foreground color, osc.c:1398-1458
Ghostty	✓	v1.0.0
iTerm2	✓	v20260216-nightly
Kitty	✓	Yes	Set/query foreground color via set_dynamic_color
Konsole	✓	Yes	TextColor enum value 10 in src/session/Session.h:416, reportForegroundColor in src/session/Session.cpp:986
mintty	✓	Yes	Implemented at termout.c:4700, set/query default foreground color
mlterm	✓	rel-3_0_7
PuTTY	✗	No	Not implemented in do_osc function
Rio	✓	v0.0.28	Supports both setting and querying with '?'
rxvt-unicode	✓	rxvt-unicode-7.0	Supports querying and setting default foreground color
st	✓	0.8.5	Supports both set and query operations
terminology	✓	v1.5.0
VT100	✗	No
VTE	✓	Yes	OSC 10 (XTERM_SET_COLOR_TEXT_FG) handled in vteseq.cc
WezTerm	✓	Yes	OSC 10 TextForegroundColor with query support - see wezterm-escape-parser/src/osc.rs:60,234-253,381-392,471
Windows Terminal	✓	Yes	SetForegroundColor case via SetXtermColorResource/RequestXtermColorResource
xterm	✓	Yes	OSC 10 changes VT100 text foreground color (OSC_TEXT_FG=10 in ptyx.h:1018)
xterm.js	✓	4.16.0
Multiplexers
cy	✓	Yes
GNU Screen	✗	No
tmux	✓	2.6	Set/query default foreground color
tuios	✓	v0.0.15
Zellij	~	v0.12.0	Query only, setting not supported

Syntax​

Parameters​

Response​

Description​

Examples​

Specifications​

Terminal support​

See also​