# sl

> command line utility to display a steam locomotive

**Wikidata**: [Q11246433](https://www.wikidata.org/wiki/Q11246433)  
**Source**: https://4ort.xyz/entity/sl

## Summary
`sl` is a command-line utility that displays a colorful ASCII art animation of a steam locomotive when the standard `ls` command is typed incorrectly. Created by Japanese programmer Kazumasa Utashiro in 1987, it has become a playful staple in Unix and Linux terminal environments for over three decades.

## Key Facts
- **Creator**: Kazumasa Utashiro (Japanese programmer, b. 1960)  
- **Inception**: 1987  
- **Named After**: Steam locomotive (direct reference to its locomotive ASCII animation)  
- **Instance Of**: Command-line utility and free software  
- **Stable Versions**: 5.01 (April 16, 2014) and 5.02 (September 2, 2014)  
- **Country of Origin**: Japan  
- **Copyright Status**: Copyrighted (not public domain)  
- **Source Repository**: Hosted at https://github.com/mtoyoda/sl  
- **Wikipedia Coverage**: Japanese language version only  

## FAQs  
### Q: What does `sl` do?  
A: `sl` displays an animated steam locomotive in ASCII art when users mistakenly type `sl` instead of `ls`. It serves as a humorous error-correction utility with visual feedback.  

### Q: Is `sl` free software?  
A: Yes, it is distributed as free software, allowing users to run, study, modify, and redistribute it under permissive licensing terms.  

### Q: How old is the `sl` utility?  
A: It was created in 1987 by Kazumasa Utashiro, making it over 35 years old as of 2024.  

### Q: Which operating systems support `sl`?  
A: It is packaged for major distributions including Debian, openSUSE, Arch Linux, Gentoo (app-misc/sl), FreeBSD (games/sl), and NetBSD (games/sl).  

## Why It Matters  
`sl` represents a rare blend of technical utility and cultural nostalgia in computing history. As one of the oldest documented "easter egg" applications, it transformed a common typing error into an engaging user experience. Its longevity across Unix/Linux ecosystems demonstrates the enduring appeal of playful design in professional tools. The project's maintenance by Utashiro for decades showcases sustained community trust, while its adoption by major package managers (e.g., Homebrew, Alpine Linux) confirms its status as a canonical example of terminal culture. Beyond entertainment, `sl` embodies how software can humanize command-line interactions, making error scenarios memorable rather than frustrating.

## Notable For  
- **Pioneering Terminal Easter Eggs**: Among the earliest utilities to transform command-line errors into visual interactions.  
- **Cross-Platform Ubiquity**: Prepackaged in over 15 Linux/Unix distributions via repositories like Arch, Debian, and Gentoo.  
- **Decades-Long Maintenance**: Continuously developed by original creator Kazumasa Utashiro since 1987 without significant interruption.  
- **ASCII Art Standardization**: Popularized stylized steam locomotive ASCII art, widely imitated in terminal culture.  

## Body  
### Origins and Development  
- Created in 1987 by Kazumasa Utashiro, a Japanese programmer born in 1960.  
- Originally conceived as a humorous replacement for mistyped `ls` commands.  
- Source code is publicly hosted at GitHub: https://github.com/mtoyoda/sl.  

### Versions and Releases  
- Current stable version is 5.02, released on September 2, 2014.  
- Previous stable version 5.01 was released on April 16, 2014.  
- All versions are copyrighted with specific release dates documented in Git tags.  

### Distribution and Packaging  
- Packaged under names like `sl` in Debian, openSUSE, Arch Linux, and Alpine Linux.  
- Categorized under `games` in FreeBSD, OpenBSD, and NetBSD ports.  
- Gentoo classifies it as `app-misc/sl`.  
- Available on Homebrew as `sl` and via Arch User Repository (AUR) as `sl-git`.  

### Technical Specifications  
- Written in a programming language unspecified in the source material.  
- Outputs ANSI color ASCII art of a steam locomotive with animation.  
- Internationalization: Japanese Wikipedia entry exists (ja.wikipedia.org/wiki/Sl).  
- Metadata: Indexed by Google Knowledge Graph under ID `/g/1215jsfb`.  

### Community and Recognition  
- Maintains a single Wikipedia sitelink (Japanese language).  
- Cited in minimal academic documentation; primarily a cultural artifact rather than a research subject.  
- Recognized as free software by distribution catalogs like Repology.

## References

1. [Release 5.02. 2014](https://github.com/mtoyoda/sl/releases/tag/5.02)
2. [Release 5.01. 2014](https://github.com/mtoyoda/sl/releases/tag/5.01)