nosh vs zsh

See how nosh compares to zsh with spaceship-prompt, one of the most popular prompt frameworks.

Startup Speed

90x faster

Time to first prompt

zsh + spaceship

155ms

nosh

1.7ms

Every command you run, you save 153ms waiting for your prompt. That's instant feedback instead of a noticeable delay.

Why so fast?

Factor	zsh + spaceship	nosh
Language	Interpreted shell scripts	Compiled Rust binary
Plugin execution	Sequential shell commands	Parallel async tasks
Git detection	Spawns `git` processes	Native library (libgit2)
Startup	Sources .zshrc, frameworks	Direct binary execution

Feature Comparison

Feature	zsh + spaceship	nosh
Startup time	~155ms	~2ms
Bash compatible	Partial	Full
Plugin format	Shell scripts	TOML config
Theme format	Shell scripts	TOML config
Completion format	Shell scripts	TOML config
AI commands	Requires external tools	Built-in
Async prompts	Via zsh-async	Native (100ms soft timeout)
Language detection	Shell commands per prompt	Cached native detection
Memory usage	~15-30MB	~8MB
Written in	C + shell	Rust

Configuration Comparison

Theme Configuration

zsh + spaceship (shell script)

# ~/.zshrc
SPACESHIP_PROMPT_ORDER=(
  dir
  git
  node
  rust
  exec_time
  line_sep
  char
)
SPACESHIP_CHAR_SYMBOL="❯"
SPACESHIP_DIR_COLOR="blue"

nosh (TOML)

# ~/.config/nosh/themes/mytheme.toml
[prompt]
format = """
[{dir}](blue bold) [{git_branch}](purple)
[{rust_version}](red) [{node_version}](green)
[{prompt:char}](green) """
char = "❯"

Plugin Creation

zsh (shell script)

# weather.plugin.zsh
spaceship_weather() {
  local temp
  temp=$(curl -s 'wttr.in?format=%t')
  spaceship::section \
    --color "cyan" \
    --symbol "🌡️" \
    "$temp"
}

nosh (TOML)

# weather.toml
[plugin]
name = "weather"

[provides]
temp = { command = "curl -s 'wttr.in?format=%t'" }

What You Keep

Switching to nosh doesn't mean starting over:

Your scripts work — nosh is Bash-compatible, so existing scripts run unchanged
Your muscle memory — Same commands, same shortcuts, same workflow
Your tools — git, docker, npm, cargo — everything works the same

What You Gain

Instant prompts — No more waiting for your prompt to render
Simpler config — TOML instead of shell scripts
Built-in AI — Ask questions in plain English
Modern codebase — Rust means fewer crashes, better performance
Package system — Install themes and plugins with /install user/repo

Benchmark Methodology

Tests run in Docker containers (Debian Bookworm) for reproducibility:

zsh 5.9 with spaceship-prompt (latest)
nosh built from source
Test environment: Git repository with Cargo.toml
Measurement: Time from process start to prompt character appearing
Runs: 50 iterations with 5 warmup runs

# Reproduce the benchmark
git clone https://github.com/poudels14/nosh
cd nosh
docker build -t nosh-benchmark -f benchmarks/Dockerfile .
docker run --rm nosh-benchmark

Ready to Try?

cargo install nosh
nosh

Your existing shell stays untouched. Try nosh and see the difference.