OSC 6 Enable Special Color

OSC 6 ; Pc ; Pf ST turns on, when Pf is not zero, or off, when it is, xterm’s use of special color Pc: 0 for bold, 1 underline, 2 blink, 3 reverse, 4 italic. While a mode is on, text with that attribute is drawn in its special color. OSC 106 is the same as OSC 6, and a pair can be repeated, OSC 6 ; 0 ; 1 ; 1 ; 1 ST turning on bold and underline (do_osc). The modes start as the colorBDMode, colorULMode and similar resources say, all off by default, and nothing is answered.

The number means something else to iTerm2, which uses OSC 6 ; 1 ; bg ; red ; brightness ; N ST to color its tab (see the iTerm2 page). xterm reads the 1 and then stops at bg, which is not a number, so iTerm2’s sequence changes nothing there.

A case cannot see a special color mode, which changes only how text is drawn. libghostty-vt has neither special colors nor these modes, and ignores OSC 6 and OSC 106; what a case can see, that nothing is printed or answered, is the same as in xterm.

Validation

OSC6-1: Nothing on screen, nothing answered

A
\e]6;0;1\a        # bold in its special color
\e]106;0;0;1;1\a  # bold off, underline on
\e]6;1;bg;red;brightness;255\a  # iTerm2's tab color
B

|AB____|
cursor 1,3
reply none