Install yash with Homebrew

Project links

• Homepage
• Repository

Commands and aliases

• yash

Project history

Upstream NEWS records Yash 2.0 alpha0 as the first 2.x release on 2008-05-26. The project later moved to GitHub; the README says it is maintained on GitHub but was formerly on OSDN, and the GitHub repository was created on 2012-11-24.

A defining thread in Yash history is conformance work. NEWS records POSIX.1-2008 conformance in Yash 2.8 in April 2009, support for the 2013 edition of POSIX.1-2008 in 2.42 in August 2016, and support for POSIX.1-2008 Technical Corrigendum 2 in 2.44 in January 2017. The current README says Yash now fully supports POSIX.1-2024 except for listed limitations.

The project has stayed actively maintained in a conservative shell-tooling style. The README describes stable maintenance releases every three months or so, and GitHub releases show 2.61 published on 2026-03-03.

Adoption history

Yash's adoption is niche compared with bash, zsh, dash, or fish, but it has a clear role for users who care about POSIX behavior, shell-language edge cases, and an interactive shell that does not primarily chase bash compatibility. Package managers such as Homebrew, MacPorts, Fedora, Nix, and Ubuntu carry it as an alternative shell rather than as a default system shell.

Its maintenance style also attracts shell implementers and portability-minded users: NEWS entries repeatedly track standard changes, built-in behavior, job control, pathname expansion, and line-editing details rather than splashy user-interface pivots.

How it is used

Users can run yash as an interactive shell, script interpreter, or login shell. The README documents startup files under `$XDG_CONFIG_HOME/yash/profile` or `~/.yash_profile` for login shells and `$XDG_CONFIG_HOME/yash/rc` or `~/.yashrc` for interactive configuration.

In practice it is useful for POSIX shell testing, portable script development, and users who want a smaller standards-oriented shell with interactive amenities such as command completion, history-based prediction, global aliases, arrays, and extended globbing.

Why package nerds care

yash is package-nerd significant because shells are both applications and compatibility surfaces. Packaging yash gives users a reproducible alternative interpreter for testing scripts against POSIX semantics without replacing the system `/bin/sh`.

It is also a good example of long-haul small-project maintenance: standards tracking, portability fixes, completion updates, and cautious release cadence matter more than branding. That makes it valuable in package collections even when its user base is specialized.

Timeline

• 2008-05-26: Yash 2.0 alpha0 is recorded as the first 2.x release.
• 2009-04-18: Yash 2.8 NEWS states conformance to POSIX.1-2008.
• 2012-11-24: magicant/yash repository is created on GitHub.
• 2016-08-27: Yash 2.42 adds support for the 2013 edition of POSIX.1-2008.
• 2017-01-17: Yash 2.44 adds support for POSIX.1-2008 Technical Corrigendum 2.
• 2026-03-03: Yash 2.61 is released; the manual version matches 2.61.

Related projects

• dash and bash are common comparison points for POSIX shell behavior and scripting compatibility.
• zsh and fish occupy the more feature-forward interactive shell space that yash partially overlaps but does not try to clone.
• yash-rs is the upstream author's Rust reimplementation project for a future extended POSIX shell.

Sources

• https://api.github.com/repos/magicant/yash
• https://api.github.com/repos/magicant/yash/releases?per_page=100
• https://github.com/magicant/yash
• https://github.com/magicant/yash-rs
• https://magicant.github.io/yash/
• https://magicant.github.io/yash/doc/
• https://raw.githubusercontent.com/magicant/yash/master/NEWS
• https://raw.githubusercontent.com/magicant/yash/master/README.md