# Differences from pre-commit

## General differences

- `prek` supports both `.pre-commit-config.yaml` and `.pre-commit-config.yml` configuration files.
- `prek` implements some common hooks from `pre-commit-hooks` in Rust for better performance.
- `prek` supports `repo: builtin` for offline, zero-setup hooks.
- `prek` uses `~/.cache/prek` as the default cache directory for repos, environments and toolchains.
- `prek` decoupled hook environment from their repositories, allowing shared toolchains and environments across hooks.
- `prek` supports `language_version` as a semver specifier and automatically installs the required toolchains.
- `prek` supports `files` and `exclude` as glob lists (in addition to regex) via `glob` mappings. See [Configuration](configuration.md#top-level-files).

## Workspace mode

`prek` supports workspace mode, allowing you to run hooks for multiple projects in a single command. Each subproject can have its own `.pre-commit-config.yaml` file.

See [Workspace Mode](./workspace.md) for more information.

## Language support

See the dedicated [Language Support](languages.md) page for a complete list of supported languages, prek-specific behavior, and unsupported languages.

## Command line interface

For a compatibility-focused command mapping, see [Compatibility with pre-commit](compatibility.md).

### `prek run`

- `prek run [HOOK|PROJECT]...` supports selecting or skipping multiple projects or hooks in workspace mode. See [Running Specific Hooks or Projects](workspace.md#running-specific-hooks-or-projects) for details.
- `prek run` can execute hooks in parallel by priority (hooks with the same [`priority`](./configuration.md#priority) may run concurrently), instead of strictly serial execution.
- `prek` provides dynamic completions of hook id.
- `prek run --last-commit` to run hooks on files changed by the last commit.
- `prek run --directory <DIR>` to run hooks on a specified directory.

### `prek list`

`prek list` command lists all available hooks, their ids, and descriptions. This provides a better overview of the configured hooks.

### `prek auto-update`

- `prek auto-update` updates all projects in the workspace to their latest revisions.
- `prek auto-update` checks updates for the same repository only once, speeding up the process in workspace mode.
- `prek auto-update` supports `--dry-run` option to preview the updates without applying them.
- `prek auto-update` supports the `--cooldown-days` option to skip releases newer than the specified number of days (based on the tag creation timestamp for annotated tags, or the tagged commit timestamp for lightweight tags).

### `prek sample-config`

- `prek sample-config` command has a `--file` option to write the sample configuration to a specific file.

### `prek cache`

- `prek cache clean` to remove all cached data.
- `prek cache gc` to remove unused cached repositories, environments and toolchains.
- `prek cache dir` to show the cache directory.
- `prek cache size` to show the total size of the cache.

## Not implemented

The `pre-commit hazmat` subcommand introduced in pre-commit
[v4.5.0](https://github.com/pre-commit/pre-commit/releases/tag/v4.5.0) is not
implemented. This command is niche and unlikely to be widely used.