whence

A command-line tool for locating executables in your PATH, written in Rust.

Why?

Traditional which implementations work fine. This one has colors and uses threads.

Features

• Concurrent PATH scanning - Parallel directory traversal (because why not)
• Colorized output - Visual distinction between executables and symlinks
• Detailed file information - Permissions, sizes, and modification times
• Symlink resolution - See where those links actually point
• Duplicate detection - Identify and filter duplicate PATH entries
• Performance statistics - Detailed timing and search metrics
• JSON output - Machine-readable output for automation

Installation

cargo install --path .

Installs both whence and wnc binaries.

Usage

Find a command:

whence cargo

Show all matches in PATH:

whence -a python3

Display detailed file information:

whence -l cargo
# rwxr-xr-x     7.2M Jan 15 22:35 /Users/you/.cargo/bin/cargo

Resolve symbolic links:

whence -L python3
# /opt/homebrew/bin/python3
#   └→ /opt/homebrew/Cellar/[email protected]/3.13.5/Frameworks/Python.framework/Versions/3.13/bin/python3.13

Remove duplicate results:

whence -a -u python3

Show performance metrics:

whence --stats cargo

Output as JSON:

whence --json -l -L python3

Performance

Roughly 3x slower than which. The extra features come at a cost.

Benchmark 1: whence cargo
  Time (mean ± σ):       2.5 ms ±   3.1 ms

Benchmark 2: which cargo
  Time (mean ± σ):     783.5 µs ± 3411.4 µs

For interactive use, the difference is imperceptible. For tight loops, use which.

Development

cargo test              # Run tests
cargo build --release   # Build optimized binary
cargo clippy            # Pedantic mode enabled

License

MIT or Apache 2.0, your choice.