Why does \x1b[8m-hidden text show up when I copy it out of the terminal?

Conceal hides the *rendered glyphs* — the text bytes still sit in the terminal's cell buffer, and selection / copy reads from that buffer, not from what's painted on screen. Terminal-screen tools behave the same way (screen-scrapers, accessibility readers, tmux capture-pane). Treat SGR 8 as a *display* obfuscation, never a security boundary — fine for the classic CTF-style hidden flag, never for passwords or secrets.

Does \x1b[8m survive script or asciinema recordings?

Yes — both tools record the raw byte stream the application emitted, including SGR 8. Replaying through a terminal that honours conceal will hide the text on screen; piping the recording through cat -A or sed 's/\x1b\[[0-9;]*m//g' reveals the underlying bytes. SGR 8 is a render-time directive, not a storage transform.

SGR 8 — Conceal / Hidden

Render following text invisibly (cursor still advances).

Byte forms

Every common string-literal form so you can paste-and-search either direction.

\\x1b[\x1b[8m

\\033[\033[8m

\\e[\e[8m

ESC [ESC [ 8 m

hex1b 5b 38 6d

Description

Sets the foreground to be visually identical to the background — the text still occupies cells and is preserved by select-all/copy. Useful for spoiler tags or password-style display, but NOT a security primitive: the text is copyable. Disable with \x1b[28m. Most modern terminals honor it; Linux console and ConPTY treat it as a no-op.

Spec citation: ECMA-48 §8.3.117 (SGR parameter 8)

Examples

bash

printf 'password: \033[8mhunter2\033[28m (select to reveal)\033[0m\n'

python

print('\x1b[8mhidden\x1b[0m')

fmt.Print("\x1b[8mhidden\x1b[0m")

javascript

console.log('\x1b[8mhidden\x1b[0m')

printf("\x1b[8mhidden\x1b[0m\n");

Frequently asked

Short answers to the questions developers actually search for this sequence.

Why does \x1b[8m-hidden text show up when I copy it out of the terminal?: Conceal hides the *rendered glyphs* — the text bytes still sit in the terminal's cell buffer, and selection / copy reads from that buffer, not from what's painted on screen. Terminal-screen tools behave the same way (screen-scrapers, accessibility readers, tmux capture-pane). Treat SGR 8 as a *display* obfuscation, never a security boundary — fine for the classic CTF-style hidden flag, never for passwords or secrets.
Does \x1b[8m survive script or asciinema recordings?: Yes — both tools record the raw byte stream the application emitted, including SGR 8. Replaying through a terminal that honours conceal will hide the text on screen; piping the recording through cat -A or sed 's/\x1b\[[0-9;]*m//g' reveals the underlying bytes. SGR 8 is a render-time directive, not a storage transform.

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: yes
GNU screen: yes

xterm	Linux console (fbcon)	macOS Terminal.app	iTerm2	Windows Terminal	cmd.exe / ConPTY	kitty	alacritty	WezTerm	Ghostty	GNOME Terminal	Konsole	tmux	GNU screen
yes	no	yes	yes	yes	no	yes	yes	yes	yes	yes	yes	yes	yes

Byte forms

Description

Examples

Frequently asked

Terminal support

Related sequences