Elvish, expressive programming language and a versatile interactive shell

Original Article ↗ Hacker News Discussion ↗

Elvish is presented as a modern, expressive shell that borrows ideas from PowerShell, fish, Tcl and Lisp to offer structured data, safer defaults, richer interactivity and a more consistent scripting language than traditional POSIX shells. Commenters weigh these advantages against the ubiquity and standardization of bash, noting concerns about learning “yet another shell,” ecosystem maturity, and compatibility with existing scripts and workflows. The thread also touches on design choices like lambda syntax, job control, TUIs, and language‑server support, highlighting both enthusiasm for experimentation in shells and skepticism that any newcomer can realistically displace bash in the near term.

Project overview & goals

  • Elvish is presented as an expressive shell with a structured, non-string-centric language, aiming to combine:
    • PowerShell-style structured data,
    • “Unix-y” sensibilities of traditional shells,
    • interactive UX focus similar to fish.
  • Intended to be both an interactive shell and a serious scripting language with fewer pitfalls than POSIX shells.

Syntax, semantics & safety

  • Examples highlight:
    • safer glob handling (no “*.jpg” when no matches),
    • less quoting boilerplate, more explicit string operations (str:trim-suffix vs ${x%y}),
    • first-class lists, maps, lambdas, arbitrary-precision integers and rationals.
  • Some find the syntax changes “cosmetic” or trivial compared with bash; others argue these avoid common bugs and footguns and improve daily ergonomics.
  • Lambda syntax {|arg| ... } is discussed; it evolved from earlier forms and resembles Ruby/Smalltalk.

Comparison with other shells & languages

  • Compared to:
    • bash/ksh: more consistent, fewer edge-case traps, but lacks ubiquity.
    • fish: Elvish scripting seen as nicer; fish autocomplete considered superior by some.
    • Nushell, Murex: similar focus on structured data; job control support varies.
    • PowerShell: similar data orientation but Elvish avoids heavy OO and slow startup.
    • Tcl and others (Julia, Python, Guile) mentioned as alternative scripting options.

Adoption, compatibility & “real-world” value

  • Some argue new shells don’t address the “trillion hacky things” done in bash and will remain niche toys.
  • Others emphasize:
    • incremental adoption (use Elvish for either interactive use or new scripts only),
    • that shells are largely about “cosmetic convenience” and that ergonomics matter.
  • Standardization and ubiquity are cited as reasons to stick with bash despite its flaws.

Author clarifications & roadmap

  • Encourages viewing Elvish as an additional tool, not a hard switch.
  • Future ideas:
    • easier construction of lightweight TUIs (“TUIlets”) from scripts,
    • better homelab/build-farm management tooling,
    • stronger LSP/editor integration,
    • possible improvements to autocomplete (fish-like suggestions) and job control (e.g., ^Z).
  • Documentation quality and built-in LSP are repeatedly praised.