C0 controls — BS, HT, LF, CR, BEL (single-byte codes)

Byte forms

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

Description

These five single-byte controls predate ANSI/VT and are still acted on by every terminal: **BS** (0x08, `\b`) moves the cursor one cell left (does NOT erase — pair with a space + BS again to erase, or use EL). **HT** (0x09, `\t`) advances the cursor to the next tab stop (default every 8 columns). **LF** (0x0a, `\n`) moves down one line (and, with `onlcr` tty mode, returns to column 1 — Unix shells rely on this, which is why a raw `\n` looks ladder-stepped under `stty -onlcr`). **CR** (0x0d, `\r`) returns to column 1 of the current line — used for progress bars (`\r` + redraw). **BEL** (0x07, `\a`) rings the audible bell or flashes the visual bell depending on the terminal's setting; it also serves as the de-facto OSC string terminator (see OSC 0/2 and OSC 8). None of these consume an `ESC` byte — they are part of the C0 control set inherited from ASCII (1963) / ECMA-6.

Spec citation: ECMA-48 §8.2 (C0 set) / ASCII / ECMA-6

Parameters

Examples

printf '\rprogress: 50%%\r'   # CR redraws current line\nprintf 'beep\a\n'           # BEL rings the bell

import sys, time\nfor i in range(101):\n  sys.stdout.write(f'\r{i}%'); sys.stdout.flush(); time.sleep(0.02)

fmt.Print("\rprogress: 50%\r")

process.stdout.write('\rprogress: 50%\r')

printf("\rprogress: 50%%\r");

Terminal support

xterm

yes

Linux console (fbcon)

yes

macOS Terminal.app

yes

iTerm2

yes

Windows Terminal

yes

cmd.exe / ConPTY

yes

kitty

yes

alacritty

yes

WezTerm

yes

Ghostty

yes

GNOME Terminal

yes

Konsole

yes

tmux

no

GNU screen

no

Related sequences

• CUU / CUD / CUF / CUB — Move cursor
• CHA — Cursor horizontal absolute (column)
• EL — Erase in line (\x1b[K)
• RIS — Reset to Initial State (full terminal reset)