# sha256

## Calculating the SHA256

The `sha256` value is usually calculated by the command:

```bash
$ shasum -a 256 <file>
```

## Special Value `:no_check`

The special value `sha256 :no_check` is used to turn off SHA checking whenever checksumming is impractical due to the upstream configuration.

`version :latest` requires `sha256 :no_check`, and this pairing is common. However, `sha256 :no_check` does not require `version :latest`.

We use a checksum whenever possible.