Krantz ~ a fast ZSH alternative written in Nim
Compiled • YAML Command Policy • History

nimble install krantz

API reference

Note

Krantz is still a work in progress, but already pretty usable as a daily driver

😍 Key Features

• Interactive REPL with line editing and tab completion
• POSIX-style expansion: tilde, env vars, command substitution, glob (via delegated shell)
• Variable assignment (FOO=bar) with export / unset
• Pipelines, redirections, background processes, conditional operators
• Policy engine to deny dangerous commands
• Persistent storage for history
• Styled configurable prompt (user, host, git, cwd)
• OSC 7 terminal cwd tracking
• YAML configuration (~/.krantz/config.yaml)
• Builtins: cd, exit, history, trash, export, unset

Install

You need nim. Once built add it to your /etc/shells, then in Terminal app add the absolute path

Line Editing

Emacs keybindings, history search (Ctrl-R), kill/yank ring, incremental search, three-phase file path completion (case-insensitive on macOS).

Expansion

Tilde (~, ~user) expansion is handled natively. All $-based expansion (environment variables, ${:-=+?} operators, command substitution, arithmetic) and backtick substitution is delegated to /bin/sh via fork/exec, ensuring full shell compatibility. Globbing (*, ?, [...]) is handled natively. Expansion order follows POSIX semantics.

Terminal Integration

OSC 7 cwd emission for same-directory new tabs. Graceful SIGHUP/SIGTERM shutdown. SA_RESTART for SIGWINCH. Unknown CSI sequences consumed. Terminal modes reset at startup.

Child processes receive proper process-group membership (setpgid) and terminal foreground ownership (tcsetpgrp) via blocked SIGTTOU/SIGTTIN, matching the POSIX job-control model. After a foreground child exits, the terminal is reclaimed and input-affecting modes (mouse tracking, focus events, bracketed paste) are reset without disturbing the child's visible output. Stale stdin is drained before each child runs.

Examples

...

Krantz Config

Configuration lives at ~/.krantz/config.yaml. First-time initialization automatically creates the config file under ~/.krantz/ with a default policy that denies dangerous commands:

policy:
  deny:
    - rm

history:
  maxSize: 1000

prompt:
  user: false       # show username in the cmd line
  host: false       # show hostname in the cmd line
  git: true         # enable git branch status
  cwdShort: false  

🗺 Roadmap

Ideas and planned features to evolve krantz into a full-featured ZSH/bash alternative:

• Job control ~ fg, bg, jobs, Ctrl-Z suspend/resume
• Completion system ~ command-specific completions (git branches, npm packages, SSH hosts, Makefile targets), programmable completion akin to zsh-completions
• Syntax highlighting ~ real-time highlighting of the input line
• Autosuggestions ~ grayed-out history-based suggestions as you type (fish/zsh-autosuggestions style)
• Vim mode ~ vi keybindings with visual/insert/normal modes
• Directory stack ~ pushd/popd/dirs for fast directory hopping
• Directory jumper ~ fuzzy directory navigation via z/zoxide-style frecency
• Plugin system ~ load external modules without recompiling the shell
• Prompt themes ~ user-switchable prompt presets with colors, segments, and status indicators
• Alias system ~ global and suffix aliases, alias expansion hints
• Keybinding config ~ user-definable keybindings via YAML
• History substring search ~ type part of a command, press up-arrow to match (like history-substring-search)
• Fuzzy matching ~ integrate fzf for Ctrl-T file search, Ctrl-R history reverse search
• Built-in help ~ help builtin with support for builtins, config, and keybindings
• Session persistence ~ save/restore REPL state (cwd, variables, history position)
• LLM integration ~ inline AI suggestions, natural-language-to-command translation
• Config hot-reload ~ apply config changes without restarting the shell
• Mouse support ~ click-to-position cursor in the REPL input line
• Shell scripting ~ execute .krantzrc and script files with krantz builtins

❤ Contributions & Support

• 🐛 Found a bug? Create a new Issue
• 👋 Wanna help? Fork it!

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🎩 License

GPLv3 license. Made by Humans from OpenPeeps.
Copyright OpenPeeps & Contributors — All rights reserved.