OSC 9;4 - Progress Bar Sequence

October 27, 2025

The OSC 9;4 sequence is a terminal escape sequence originally created by ConEmu for displaying progress bars. It has since been adopted by other terminal emulators including Ghostty and Windows Terminal.

In supporting terminals, this sequence can display a native GUI progress bar that shows operation progress, completion state, and errors.

Sequence Format #

OSC 9 ; 4 ; state ; progress ST

Where:

OSC is \x1b] (ESC followed by ])
ST is the string terminator: \x07 (BEL) or \x1b\ (ESC followed by \)
state is a single digit 0-4 indicating the progress bar state
progress is an optional value 0-100 representing the percentage complete

State Values #

State	Name	Description
0	Remove	Removes/hides the progress bar
1	Set	Sets progress bar to normal state with given progress value
2	Error	Sets progress bar to error state (typically red)
3	Indeterminate	Sets progress bar to indeterminate/pulsing state
4	Pause	Sets progress bar to paused state

Examples #

Remove progress bar:

\x1b]9;4;0\x07

Set progress to 50%:

\x1b]9;4;1;50\x07

Show error state:

\x1b]9;4;2\x07

Show indeterminate progress:

\x1b]9;4;3\x07

Show paused state at 75%:

\x1b]9;4;4;75\x07

Terminal Implementations #

ConEmu #

ConEmu, the originator of this sequence, displays progress in the taskbar and optionally in the tab title.

Ghostty #

Ghostty (version 1.2.0+) renders OSC 9;4 sequences as a native GUI progress bar at the top of the terminal window. The progress value is clamped to the range 0-100.

Konsole #

Konsole (KDE’s terminal emulator) supports OSC 9;4 sequences.

mintty #

mintty (Cygwin/MSYS2/WSL terminal) added support in November 2020 (version 3.4.2). In addition to the standard numeric states, mintty also supports mnemonic parameters like OSC 9;progress;green, OSC 9;progress;red, OSC 9;progress;busy, etc.

WezTerm #

WezTerm added support in February 2025. Implements all standard states: none, set percentage, error, indeterminate, and paused.

Windows Terminal #

Windows Terminal displays the progress in the Windows taskbar, updating the taskbar icon to show progress state and percentage.

xterm.js #

xterm.js provides support via the @xterm/addon-progress addon. Supports all states: remove, normal, error, indeterminate, and pause/warning.

Notes #

The sequence OSC 9;4 followed by anything other than a semicolon and valid state is interpreted as a desktop notification by ConEmu-compatible terminals, not a progress bar.

Progress values outside the range 0-100 are clamped to that range by the terminal.