OSC 2 Set Window Title

Set the window title to Pt, which is UTF-8 text. Ps says which title:

Nothing on the screen changes. The sequence can end with ST (ESC \) or, as most programs that set titles do, with BEL.

A shell sets this from its prompt, which is how a tab comes to show the directory you are in or the command that is running.

The older forms. Before these, Sun’s terminals and CDE’s dtterm set the title with a letter instead of a number, and xterm accepts them too: its Control Sequences document lists them in its table of the Sun and dtterm window operations.

There is no ;: everything after the letter is the text, a ; included (do_osc). These are also the forms xterm answers in when it reports the title or the icon name, CSI 21 t and CSI 20 t (see XTWINOPS), though a default xterm refuses those reports. libghostty-vt has only the numbered forms and ignores the letters, so the cases that set the title with OSC l are known differences.

Validation

OSC2-1: Ended with ST

\e]2;Hello\e\\

|___|
title "Hello"
cursor 1,1

OSC2-2: Ended with BEL

\e]2;Hello\a

|___|
title "Hello"

OSC2-3: OSC 0, with UTF-8

\e]0;café ☕\a

|___|
title "café ☕"

OSC2-4: The last one wins

\e]2;first\a
\e]2;second\a

|___|
title "second"

OSC2-5: The dtterm form

\e]lHello\e\\

|___|
title "Hello"

OSC2-6: Everything after the l is the title

\e]l;two;parts

|___|
title ";two;parts"

OSC2-7: OSC L sets only the icon name

\e]2;Window
\e]LIcon
\e]IIcon.xpm
A

|A__|
title "Window"
cursor 1,2