pwsh-prompt

A fast, minimal shell prompt for PowerShell, written in Rust.

Pre-built binaries support Windows and Linux. macOS is supported when built from source.

Features

• Lightning fast: Compiled to a small native binary with zero startup delay
• Git integration: Shows current branch and PR number with status icons (open, draft, closed) and smart caching
• Path display: Intelligently truncates long paths to fit terminal width
• Command feedback: Displays exit codes and execution duration
• System info: Shows OS and shell information
• Simple mode: Minimal prompt option for even faster rendering
• Windows Terminal integration: Shell integration escape sequences for new-tab-same-directory, scrollbar marks, and command navigation

Installation

Scoop (Windows)

scoop bucket add lucaspimentel https://github.com/lucaspimentel/scoop-bucket
scoop install pwsh-prompt

Install from GitHub Release (Recommended)

No build tools or .NET SDK required:

irm https://raw.githubusercontent.com/lucaspimentel/pwsh-prompt/main/install-remote.ps1 | iex

Or to install a specific version:

$version = "1.0.0"; irm https://raw.githubusercontent.com/lucaspimentel/pwsh-prompt/main/install-remote.ps1 | iex

Install from Source

Clone the repository and run the installation script:

./install-local.ps1

This will build the native binary (Rust toolchain required) and install it to ~/.local/bin/pwsh-prompt.

Options:

• -Force — skip confirmation prompts and overwrite existing installation
• -Update — pull latest changes from the remote before building

# Pull latest and install without prompts
./install-local.ps1 -Update -Force

Setup

Add this line to your PowerShell profile ($PROFILE):

Invoke-Expression (& ~/.local/bin/pwsh-prompt init)

Simple Mode

For a minimal prompt with just path, git, and host information:

# Edit the init output or modify your profile to use --simple
pwsh-prompt prompt --simple

Version

To check the installed version:

pwsh-prompt --version

Building Manually

The Rust implementation in src/pwsh-prompt-rs is a byte-compatible port of the C# tool and is the build target for releases and install-local.ps1.

# Rust build (release)
cargo build --release --manifest-path src/pwsh-prompt-rs/Cargo.toml

# Rust tests
cargo test --manifest-path src/pwsh-prompt-rs/Cargo.toml

The original C# project is kept intact for side-by-side comparison:

# Quick build test
dotnet build src/pwsh-prompt -c Release -f net10.0

# Publish for Windows
dotnet publish src/pwsh-prompt -c Release -r win-x64 --output ./publish

# Publish for Linux
dotnet publish src/pwsh-prompt -c Release -r linux-x64 --output ./publish

# Or build via solution
dotnet build pwsh-prompt.slnx

Benchmarks

Compare end-to-end performance (process startup plus a full render) of the Rust and C# binaries across repo, non-repo, truncation, simple mode, and PR scenarios:

pwsh -File src/pwsh-prompt-rs/bench.ps1            # 100 timed runs per scenario
pwsh -File src/pwsh-prompt-rs/bench.ps1 -RustOnly  # skip the C# comparison

The script builds either binary if it is missing, cleans the inherited PROMPT_* environment, and reports median/min plus the rust-to-c# ratio.

Project Structure

pwsh-prompt/
├── src/
│   ├── pwsh-prompt/          # Main C# project (reference implementation)
│   │   ├── Segments/         # Segment implementations (ISegment)
│   │   ├── Program.cs        # Entry point and mode routing
│   │   ├── Arguments.cs      # Command-line argument parsing
│   │   ├── GitInfo.cs        # Git repository detection and caching
│   │   ├── Init.cs           # PowerShell initialization script generator
│   │   └── ...               # Other core files
│   └── pwsh-prompt-rs/       # Rust port (byte-compatible, release target)
│       ├── src/              # One module per C# file, plus path/ANSI helpers
│       ├── init.ps1          # Init script template (extracted from the C#)
│       └── parity.ps1        # Byte-parity harness against the C# binary
├── install-local.ps1         # Build from source and install
├── install-remote.ps1        # Download from GitHub releases and install
└── pwsh-prompt.slnx          # Solution file

Architecture

The prompt uses a modular segment system where each visual element (path, git branch, exit code, etc.) implements the ISegment interface. The application runs in two modes:

1. init mode: Generates PowerShell initialization code to install the prompt
2. prompt mode: Renders the actual prompt on every invocation

Performance

Since this runs on every prompt render, performance is critical:

• Native AOT compilation eliminates JIT overhead for instant startup
• Environment variable caching avoids repeated git file I/O and gh pr view subprocess calls (cache invalidates when the discovered .git directory changes or .git/HEAD is modified — cd within the same repo reuses the cache)
• Per-branch PR cache keeps PR info for every branch visited in the current shell session, so toggling between branches doesn't re-run gh pr view
• Non-blocking PR lookup: on the first visit to a new branch, gh pr view runs in a background job so the prompt renders immediately; the PR number appears on the next prompt
• Stack-allocated buffers minimize heap allocations via ValueStringBuilder
• Smart truncation calculates exact widths for optimal path display

The PowerShell profile caches git information between prompts, avoiding file system operations when the branch hasn't changed.

License

MIT License - see LICENSE file for details.

Copyright (c) 2025 Lucas Pimentel