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nshell

A modern, fish-inspired interactive shell written in Common Lisp.

nshell is an interactive shell that puts the interactive experience first: real-time syntax highlighting, history-aware autosuggestions, fish-style abbreviations, and a fast, context-aware completion engine — all built on a clean, test-driven Common Lisp core and a reproducible Nix build.

Status: early development (0.4.x)

The interactive editor and core pipeline execution are solid and heavily tested. The shell language is a growing subset of POSIX/fish semantics — see the roadmap for what is and isn't supported yet. nshell is usable as a daily interactive shell for common workflows; it is not a script-compatible /bin/sh replacement.

Highlights

  • Syntax highlighting as you type — commands, strings, operators, and paths are colorized live.
  • Autosuggestions from your history, fish-style, accepted with → / Ctrl-F.
  • Abbreviations (abbr) that expand inline as you type — keep your muscle memory, type less.
  • Context-aware completion — a knowledge base of commands and flags plus filesystem completion, with common-prefix Tab extension and a candidate menu.
  • Rich line editing — Emacs keybindings, kill-ring and yank, multi-level undo/redo, multiline editing, and incremental history search (Ctrl-R). Optional vi key bindings (NSHELL_VI_MODE=1): normal-mode motions, counts, operators (dd, cw, …), visual selection, and insert/append.
  • Configurable prompt — hostname, working directory, git branch and dirty status, command duration, and exit code, with theming.
  • Job control — background jobs (&), jobs, fg, bg, disown.
  • Pipelines and redirection — |, >, >>, <, <<, <<<, logical && / ||, and command sequencing.
  • Control flow and functions — if, for, while, switch, begin/end, and user-defined functions.
  • Reproducible build — a single statically-dumped SBCL image via Nix; nix run and you're in.

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