The Shell Experience on Shani OS — Zsh, Starship, McFly, FZF, and More

Most Linux distributions ship a minimal shell environment and leave the rest to you. Shani OS takes the opposite approach: the shell is configured properly from the start, with tools that developers and power users usually spend hours assembling themselves.

Everything described in this post is pre-installed and active on first boot — no configuration required unless you want to customise further. Your shell configuration lives in your home directory (~/.zshrc, ~/.config/starship.toml), completely independent of the OS. It survives every OS update and rollback untouched.

Full reference: docs.shani.dev — Shell & Environment.

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The Default Shell: Zsh

Zsh is the default shell on Shani OS. Every new user account is automatically configured with /bin/zsh. Bash and Fish are also installed and available — switch with chsh -s /bin/bash or chsh -s /bin/fish if you prefer.

Zsh is configured with three plugins that bring Fish-style interactivity:

Syntax highlighting (zsh-syntax-highlighting): commands turn green as you type them if they are valid, red if they are not. Typos are visible before you press Enter.

Autosuggestions (zsh-autosuggestions): as you type, a ghost-text suggestion appears based on your command history. Press the right arrow key or End to accept the suggestion. The longer you use the shell, the more accurate the suggestions become.

History substring search (zsh-history-substring-search): press the up arrow with a partial command typed to cycle through every history entry that contains that substring — not just entries that start with what you typed.

Zsh completions (zsh-completions) are configured for hundreds of commands including git, systemctl, podman, flatpak, nix-env, and shani-deploy.

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Starship Prompt

Starship replaces the default Zsh prompt with a fast, informative, and configurable one. It is written in Rust and adds no perceptible latency to the prompt.

What Starship shows by default:

Current directory (shortened to the last two components)
Git branch and status (modified files, ahead/behind remote)
Active Python virtualenv
Node.js version (when in a Node project directory)
Rust toolchain version (when Cargo.toml is present)
Exit code of the last command (when non-zero)
Command duration (for long-running commands)

To customise your Starship configuration:

# Starship config file
nano ~/.config/starship.toml

# Example: change the prompt character
# [character]
# success_symbol = "[❯](green)"
# error_symbol = "[❯](red)"

# Full configuration reference
starship config

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McFly: Neural Network Command History

McFly replaces the standard Ctrl+R history search with a local, on-device neural network that learns from your usage patterns. It runs entirely on your machine — no data leaves your system.

Standard Ctrl+R gives you a linear search through history, most recent first. McFly gives you:

Context-aware results: commands relevant to your current directory are ranked higher
Exit-code awareness: failed commands are deprioritised
Pattern learning: commands you run frequently in a given context surface at the top
Search as you type: fuzzy matching across your full history

Press Ctrl+R to activate McFly. Type any fragment of the command you want. Navigate with arrow keys. Press Enter to execute.

McFly's database lives in ~/.local/share/mcfly/history.db — a SQLite file in your home directory that persists across everything and grows more useful over time.

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FZF: Fuzzy Finder

FZF is integrated into the Zsh configuration and provides fuzzy search for files, history, and directories via keyboard shortcuts.

Ctrl+R — History search (McFly is bound here by default; if you prefer pure FZF, switch in .zshrc)

Ctrl+T — Insert a file path. Opens a fuzzy file finder for the current directory tree. Navigate with arrow keys, type to filter. Press Enter to insert the selected path at the cursor position.

Alt+C — Change directory. Opens a fuzzy directory finder. Navigate with arrow keys, type to filter. Press Enter to cd to the selected directory.

FZF can also be used directly in scripts and pipelines:

# Interactively select from a list
ls | fzf

# Select a running process to kill
ps aux | fzf | awk '{print $2}' | xargs kill

# Select a git branch to checkout
git branch | fzf | xargs git checkout

# Search and preview files
fzf --preview 'cat {}'

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Pre-Installed CLI Tools

These tools are available immediately without installing anything:

File Search and Navigation

# ripgrep — faster grep with better defaults
rg "search term"           # search recursively from current dir
rg "pattern" src/          # search in a specific directory
rg -l "pattern"            # list only file names
rg --type py "import"      # search only Python files

# fd — modern find replacement
fd "filename"              # find files by name
fd -e py                   # find by extension
fd --type d                # find directories only
fd -x command {}           # run a command on each result

# fzf (covered above)
fzf

File Viewing

# bat — cat with syntax highlighting and line numbers
bat file.py
bat --language json file.json
bat -n file.txt            # with line numbers only

# eza — modern ls replacement
eza                        # basic listing
eza -l                     # long format
eza --tree                 # tree view
eza -la --git              # with git status per file

System Monitoring

# htop — interactive process viewer
htop

# fastfetch — system information summary
fastfetch

# ncdu — disk usage analyser (interactive)
ncdu

# tree — directory tree view
tree
tree -L 2                  # limit depth
tree --gitignore           # respect .gitignore

Text Processing

# jq — JSON processor
echo '{"key": "value"}' | jq .
curl api.example.com/data | jq '.results[].name'

# Awk, sed, grep — standard tools all present
awk '{print $1}' file.txt
sed 's/old/new/g' file.txt
grep -r "pattern" .

Compression

# 7zip handles everything
7z a archive.7z file.txt
7z x archive.7z

# Standard tools
tar xzf archive.tar.gz
unzip archive.zip
unrar x archive.rar

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Shell Configuration Files

Your shell configuration lives in your home directory:

~/.zshrc               — Zsh configuration (plugins, aliases, env vars)
~/.bashrc              — Bash configuration
~/.profile             — login shell config (shared between shells)
~/.config/starship.toml — Starship prompt configuration
~/.local/share/mcfly/  — McFly history database

All of these are in @home — completely independent of the OS. They are never touched by OS updates or rollbacks.

Adding Aliases

# Add to ~/.zshrc
nano ~/.zshrc

# Examples
alias ll='eza -la'
alias cat='bat'
alias find='fd'
alias grep='rg'
alias update='sudo shani-deploy update'
alias status='cat /data/current-slot'

Environment Variables

# In ~/.zshrc or ~/.profile
export EDITOR=vim
export PATH="$HOME/.local/bin:$PATH"
export DOCKER_HOST=unix:///run/user/$UID/podman/podman.sock

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Multiple Shells

All three major shells are installed:

# Check available shells
cat /etc/shells

# Switch default shell
chsh -s /bin/bash    # switch to Bash
chsh -s /bin/fish    # switch to Fish
chsh -s /bin/zsh     # switch back to Zsh (default)

Fish has its own syntax (not POSIX-compatible) but excellent interactive features built-in — autosuggestions, syntax highlighting, and web-based configuration all come standard. If you prefer Fish, switch with chsh and your entire interactive experience becomes Fish-based.

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Tmux

Tmux (terminal multiplexer) is pre-installed. It lets you split your terminal into panes, create multiple windows, and detach from sessions that keep running in the background.

# Start a new session
tmux

# Start a named session
tmux new -s work

# Split horizontally
Ctrl+B then %

# Split vertically
Ctrl+B then "

# Switch panes
Ctrl+B then arrow keys

# Detach from session (session keeps running)
Ctrl+B then D

# List sessions
tmux ls

# Reattach to a session
tmux attach -t work

Tmux configuration lives in ~/.tmux.conf. The default configuration on Shani OS is minimal — add your own preferences there.

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Installing Additional Shell Tools via Nix

Nix is the right tool for installing additional CLI utilities that are not pre-installed:

# Set up Nix channel first (once)
nix-channel --add https://nixos.org/channels/nixpkgs-unstable nixpkgs
nix-channel --update

# Install additional tools
nix-env -iA nixpkgs.tldr          # simplified man pages
nix-env -iA nixpkgs.bottom        # better htop
nix-env -iA nixpkgs.delta         # better git diff
nix-env -iA nixpkgs.lazygit       # terminal UI for git
nix-env -iA nixpkgs.zoxide        # smarter cd with frecency
nix-env -iA nixpkgs.starship      # update Starship if needed

All Nix-installed tools survive OS updates and rollbacks, are immediately on your $PATH, and do not touch the immutable OS root.

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Resources

Shani OS Troubleshooting Guide — when things go wrong
The Shani OS Software Ecosystem — what to use for each type of software
Your First Week with Shani OS — day-by-day setup guide
docs.shani.dev — Shell & Environment — full shell configuration reference
Nix on Shani OS — installing additional CLI tools
Distrobox on Shani OS — tools that need a full distro environment
Telegram community

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