The shemul.json file

Commands, variables and environment presets are defined in shemul.json. The keys added in 2.0.0 are all optional and backward compatible with existing files.

Key	Scope	Purpose
`os`	command	Per-OS `run` override: `windows`, `macos`, `linux` or `default`.
`bin`	top-level	Named per-OS interpreters, used as `{{name}}` or `{{bin.name}}`.
`runtime`	top-level	Default shell (`sh`, `bash`, `powershell` and so on) when a command sets none.
`shell`	command	`false` for argument-vector exec, or a shell name.
`exec`	command	An argument vector to run without a shell.
`needs`	command	Commands to run first. Deduplicated and cycle-checked.
`pre` / `post`	command	Run before or after the command. `post` runs only on success.
`parallel`	command	Run this command's `needs` concurrently.
`runner`	command	Dispatch to a plugin runner from `shemul.plugins`.
`requires`	top-level	Minimum Shemul version, for example `">=2.0.0"`.
`update_check`	top-level	Set to `false` to disable the update notifier.

Cross-OS, portable commands

json

{
  "bin": { "py": { "windows": "python", "default": "python3" } },
  "commands": {
    "run":  { "run": "{{py}} app.py" },
    "open": { "run": "xdg-open .", "os": { "windows": "start .", "macos": "open ." } },
    "info": { "run": "echo {{os}}/{{arch}}" }
  }
}

Task pipelines

json

{
  "commands": {
    "install": { "run": "npm ci" },
    "lint":    { "run": "npm run lint" },
    "test":    { "run": "npm test", "needs": ["install"] },
    "ci":      { "run": "echo green", "needs": ["lint", "test"], "parallel": true },
    "release": { "run": "npm publish", "pre": ["ci"], "post": ["echo done"] }
  }
}

The run order is always needs, then pre, then the command, then post. Magic variables need no config: {{os}}, {{arch}}, {{python}}, {{shell}}, {{sep}} and {{home}}.