Installation

The Kestrel toolchain is managed by jessup, which installs the compiler, the build tool (Flock), and the language server. Pick your platform below.

macOS

curl -fsSL https://kestrel-lang.com/install | sh

This installs jessup into ~/.jessup/bin and downloads the latest preview toolchain (kestrel, flock, kestrel-lsp, kestrel-doc). The installer adds ~/.jessup/bin to your PATH automatically by editing your shell profile (~/.zshrc, ~/.bashrc, and ~/.profile).

If your current shell hasn't picked it up yet, open a new terminal or run:

export PATH="$HOME/.jessup/bin:$PATH"

Linux

Same command:

curl -fsSL https://kestrel-lang.com/install | sh

Tested on recent Ubuntu, Debian, Fedora, and Arch. Requires glibc 2.31 or later.

Verifying

kestrel --version jessup list

kestrel --version should print a version string, and jessup list should show the active toolchain. If they don't, your shell hasn't picked up the new PATH — open a new terminal and try again.

Updating

jessup update # update installed channels (preview, nightly, …) to the latest release jessup self update # update jessup itself

Uninstalling

rm -rf ~/.jessup

Then remove the ~/.jessup/bin line the installer added to your shell profile (~/.zshrc, ~/.bashrc, or ~/.profile). Your projects are untouched.