Template Variables

Step run lines and env values in command specs are rendered as Go templates before execution. This lets you inject arguments, environment variables, and system info into your commands.

Available variables

Variable	Description
{{.args.X}}	Argument value (positional or flag) by name
{{.env.X}}	Environment variable value
{{.cwd}}	Current working directory
{{.home}}	User’s home directory

Using arguments

args:
  positional:
    - name: environment
      required: true
  flags:
    - name: replicas
      type: int
      default: "3"

steps:
  - name: deploy
    run:
      - echo "Deploying to {{.args.environment}} with {{.args.replicas}} replicas"

Running my cli run deploy -- production --replicas 5 renders the command as:

Deploying to production with 5 replicas

Using environment variables

Reference both default env vars and system environment variables:

defaults:
  env:
    GREETING: Hello

steps:
  - name: greet
    run:
      - echo "{{.env.GREETING}} from {{.env.USER}}"

Using system paths

steps:
  - name: info
    run:
      - echo "Running from {{.cwd}}"
      - echo "Home is {{.home}}"
      - cat {{.home}}/.config/app.yaml

Go template syntax

Since these are Go templates, you can use standard Go template functions:

steps:
  - name: example
    run:
      # Conditionals
      - '{{if .args.verbose}}set -x{{end}}'
      # Default values
      - echo "Region: {{or .args.region "us-east-1"}}"

Environment in steps

You can also use templates in step-level env values:

steps:
  - name: build
    env:
      DEPLOY_TARGET: "{{.args.environment}}"
      CONFIG_PATH: "{{.home}}/.config/deploy.yaml"
    run:
      - ./build.sh

Next steps

Creating Commands Full spec authoring guide.

Spec Format Reference Complete field reference.