Settings & dotenv

How to configure a Runefile and feed values to task bodies. Part of the guides; full syntax in the language guide.

Concept

Variables (name := value) are reusable values resolved statically and interpolated with {{ }}. Settings (set ...) configure the whole file. A project .env file is loaded into task environments, so configuration and secrets come from the environment — never hard-coded.

Syntax

out := "dist"
# `/` joins paths (forward slash on every OS).
bin := out / "app"

# Export Runefile variables into task environments.
set export
# Override the shell for (sh) bodies (rarely needed).
set shell := ["bash", "-euo", "pipefail"]

build:
    @echo "building {{bin}}"

A .env beside the Runefile is loaded automatically:

GREETING=hello

Runnable example

See examples/settings-dotenv — set export plus a .env value reaching the body.

Pitfalls

• Secrets live in the environment, not the Runefile. Put them in .env (kept out of version control) or the real environment. They never belong in a committed Runefile, and are never exposed to agents (see AI agents). As a safety net, values of sensitive-looking variables are masked as *** in all output — see secret masking.
• set export is opt-in. Without it, Runefile variables interpolate into commands but aren’t necessarily present as environment variables for sub-processes.
• Paths use /. The path-join operator emits forward slashes on every OS for portability.
• set shell runs the body as one script. Include -e so a failing line stops the task. The @ and - prefixes have no effect. See shell override.

Next steps

• Parameters — per-invocation inputs (vs. file-level settings).
• Executors — how the environment reaches each body.