# Command line

The reference below is taken from the program's own `--help`. If the two
disagree, the program is right and this file is a defect.

## Synopsis

```sh
nuntius [--version] [--check-config]
```

With no flags, nuntius loads the configuration, serves the form endpoints,
and shuts down gracefully on SIGINT or SIGTERM.

## Global flags

| Flag | Effect |
|---|---|
| `--help`, `-h` | prints the usage |
| `--version` | prints the release and exits: the tag at a tag, a pseudo-version naming the commit otherwise, `(devel)` outside version control, `+dirty` appended on a dirty tree |
| `--check-config` | loads and validates the configuration, then exits without listening; prints `configuration OK: <path>` on success, names the problem and exits nonzero on any error, so it runs as a systemd `ExecStartPre` |

Every flag is long-only, and Go's `flag` package accepts it with one or two
leading hyphens, so `-version` and `--version` are the same flag.

## Environment and files

`NUNTIUS_CONFIG` moves the configuration file away from
`/etc/nuntius/config.toml`. The full schema lives in
[`CONFIGURATION.md`](CONFIGURATION.md).

## Exit codes

| Code | Meaning |
|---|---|
| `0` | the version was printed, the configuration is valid, or the server shut down cleanly |
| `1` | the configuration is missing, invalid or fails validation, or the server failed to serve |

## Examples

Print the release:

```sh
nuntius --version
# nuntius v1.0.0
```

Validate a configuration without listening, as a deploy pipeline would:

```sh
NUNTIUS_CONFIG=./config.toml nuntius --check-config
# configuration OK: ./config.toml
```

## Manual page

A roff copy of this reference ships as `man/nuntius.1` in the repository
and installs with the binary; read it with:

```sh
man ./man/nuntius.1
```