# Using Documents

From macOS User Guide:

* [Open documents](https://support.apple.com/guide/mac-help/open-documents-mchl971293e1/12.0/mac/12.0)
* [Create and work with documents](https://support.apple.com/guide/mac-help/create-and-work-with-documents-mchldc1dd114/12.0/mac/12.0)
* [View and restore past versions of documents](https://support.apple.com/guide/mac-help/view-and-restore-past-versions-of-documents-mh40710/12.0/mac/12.0)

### Own Your Data

Bike is a document based app that uses open file formats.

This combination gives you full ownership of your data. Your notes and thoughts aren't locked behind a proprietary web-service. They aren't hidden away in a database available for [export only](https://twitter.com/andy_matuschak/status/1452438176996347907).

In Bike your data is fully within your control, stored in normal document files right on your computer. These files use open file formats. Even if you delete Bike from your computer you should still be able to view and edit your outlines.

### Format Options

![Format Options](/files/GOljk4GLAENAnHsAG2Bw)

`.bike`: This is Bike's native format and the one I would recommend using. It supports all Bike features. It is also an HTML document – you can view Bike files in your web browser.

`.opml`: This is a standard format for saving outlines. Use `.opml` if you wish to edit your outline with Bike and another [OPML compatible application](/bike-compatible-apps.md).

`.txt`: Bike can also work with plain text files. The outline structure is determined by the leading tab indentation. Text files don't offer any good place to store metadata (such as item ids). For this reason some features (such as links to rows) will break when you close and then reopen a `.txt` based outline.

### Open Options

When you open a document Bike can expand rows (or not) for you. To set which rows are expanded when you open a document use Settings > Document > When Open...

This setting is for when you open a document while Bike is running. When Bike re-opens a document when starting it will restore the exact row expand/collapse state. For more information on restoring documents see [Using Windows](/using-bike/using-windows.md).

### File Extensions

When you save a Bike document the filename will default to a `.bike`, `.opml`, or `.txt` file extension. This is usually what you want.

If it's not what you want you have the option to use your own file extension. For example you may wish to save "Bike" files with a `.html` file extension, or you might want to save "Plain Text" documents with a `.md` file extension.

#### To use a custom file extension

* Type the file extension after the file name in the "Save As" text field in the document save panel.

#### To load an outline that has a custom file extension

Open the file normally and Bike with detect the content format. When Bike loads an unknown file extension it performs these steps:

1. Read as Bike, if that fails then...
2. Read as OPML, if that fails then...
3. Read as Plain Text, which should never fail

These same steps are followed when reading text from the pasteboard.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://bikeguide.hogbaysoftware.com/using-bike/using-documents.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.