SGR 9 — Strikethrough

Byte forms

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Description

ECMA-48 §8.3.117 names SGR 9 "crossed-out". The byte sequence is \x1b[9m. The terminal draws a horizontal line through the middle of every subsequent character cell; the underlying text remains unmodified — selectable, copyable, screen-reader-visible — only the rendering is altered. Naming is inconsistent across documentation: ECMA-48 says "crossed-out", terminfo uses smxx / rmxx (the s-m-x-x mnemonic for "start mode x crossed-out"), and most user-facing tools say "strikethrough" or "strike". The matching close is SGR 29 (\x1b[29m), which removes the line without disturbing fg / bg / bold / italic / underline state.

Strikethrough is the post-2010 SGR attribute with the broadest support across the major GUI emulators in the matrix above — xterm, iTerm2, kitty, alacritty, wezterm, gnome-terminal, Konsole, Ghostty, Apple Terminal.app (since macOS 10.7 Lion, 2011), and Windows Terminal all render it. The exceptions are predictable: Linux console / fbcon ignores SGR 9 (no glyph-overlay renderer in framebuffer mode), legacy Windows cmd.exe pre-ConPTY drops it. The notable multiplexer gotcha is GNU screen: BOTH screen 4.x AND screen 5.0 strip SGR 9 along with OSC 8 hyperlinks and styled underlines (the screen-strips-modern-sgr quirk documented in lib/terminals.ts) — they never reach the outer terminal. tmux forwards SGR 9 if the outer terminfo claims the smxx / rmxx caps; most modern terminfo entries do, but the older screen-256color entry does not, so a tmux session that has set default-terminal "screen-256color" silently drops strikethrough — the fix is set -g default-terminal "tmux-256color" or xterm-256color.

Disable with SGR 29 (\x1b[29m). The classic application is rendering deleted lines in diff viewers and crossed-out items in TODO / CLI checklists — git diff itself does not emit strikethrough (it relies on red + leading -) but custom diff renderers like delta and difftastic optionally use it for the "removed" side. Per color-only-signal, avoid using strikethrough as the sole signal for "deleted" content: terminals that strip the attribute (Linux console, GNU screen, legacy cmd.exe) will leave the text visually identical to live content. Pair it with an explicit prefix ([del], ~~, leading -) so the meaning still arrives even when the line is dropped. Related: sgr-underline (SGR 4 — the adjacent line-decoration attribute), sgr-italic (SGR 3 — commonly mixed with strikethrough for "superseded / old" content), sgr-reset (SGR 0 — full reset).

Spec citation: ECMA-48 §8.3.117 (SGR parameter 9)

Examples

printf '\033[9mdeleted line\033[29m\n'

print('\x1b[9mdeleted\x1b[0m')

fmt.Print("\x1b[9mdeleted\x1b[0m")

console.log('\x1b[9mdeleted\x1b[0m')

printf("\x1b[9mdeleted\x1b[0m\n");

Terminal support

xterm

yes

Linux console (fbcon)

no

macOS Terminal.app

yes

iTerm2

yes

Windows Terminal

yes

cmd.exe / ConPTY

no

kitty

yes

alacritty

yes

WezTerm

yes

Ghostty

yes

GNOME Terminal

yes

Konsole

yes

tmux

partial

GNU screen

no

Related sequences

• SGR 4 — Underline
• SGR 3 — Italic
• SGR 0 — Reset / Normal