The sl Steam Locomotive Easter Egg

Typing sl instead of ls sends a train across your terminal.

macOSTerminalASCII artLow risk

Run sl and an ASCII steam locomotive chugs across the screen.

01Command

Command

$ sl

02What it does

sl exists to catch the very common typo of ls as sl. It animates a locomotive and accepts variants: -l for a little engine, -F for a flying train and -a for an accident.

03Risk

RiskLow risk

Requirementsbrew install sl

CompatibilitymacOS with Homebrew installed

!Warning: It is purely a joke command and blocks the terminal until the animation ends, so do not use it in scripts.

04Undo

✓No undo needed — this command does not change persistent state.

05Sources

Homebrew formula: sl
Homebrew · vendor-doc · 2026-09-20
Evidence: Installs sl, a joke command that displays a steam locomotive when ls is mistyped.
mtoyoda/sl
GitHub · vendor-doc · 2026-09-20
Evidence: Original sl source; options include -a accident, -l little, -F fly and -c C51.

Last verified: 2026-09-20 · Category: Developer