| # Plugins | |
| Nu can be extended using plugins. Plugins behave much like Nu's built-in commands, with the added benefit that they can be added separately from Nu itself. | |
| Nu plugins are executables; Nu launches them as needed and communicates with them over [stdin, stdout, and stderr](https://en.wikipedia.org/wiki/Standard_streams). Nu plugins can use either JSON or MSGPACK as their communication encoding. | |
| ## Adding a plugin | |
| To add a plugin, call the [`register`](/commands/docs/register.md) command to tell Nu where to find it. As you do, you'll need to also tell Nushell what encoding the plugin uses. | |
| Please note that the plugin name needs to start with `nu_plugin_`, Nu uses the name prefix to detect plugins. | |
| Linux+macOS: | |
| ```nu | |
| > register ./my_plugins/nu_plugin_cool | |
| ``` | |
| Windows: | |
| ```nu | |
| > register .\my_plugins\nu_plugin_cool.exe | |
| ``` | |
| When [`register`](/commands/docs/register.md) is called: | |
| 1. Nu launches the plugin, and waits for the plugin to tell Nu which communication encoding it should use | |
| 2. Nu sends it a "Signature" message over stdin | |
| 3. The plugin responds via stdout with a message containing its signature (name, description, arguments, flags, and more) | |
| 4. Nu saves the plugin signature in the file at `$nu.plugin-path`, so registration is persisted across multiple launches | |
| Once registered, the plugin is available as part of your set of commands: | |
| ```nu | |
| > help commands | where command_type == "plugin" | |
| ``` | |
| ## Examples | |
| Nu's main repo contains example plugins that are useful for learning how the plugin protocol works: | |
| - [Rust](https://github.com/nushell/nushell/tree/main/crates/nu_plugin_example) | |
| - [Python](https://github.com/nushell/nushell/blob/main/crates/nu_plugin_python) | |
| ## Debugging | |
| The simplest way to debug a plugin is to print to stderr; plugins' standard error streams are redirected through Nu and displayed to the user. | |
| ## Help | |
| Nu's plugin documentation is a work in progress. If you're unsure about something, the #plugins channel on [the Nu Discord](https://discord.gg/NtAbbGn) is a great place to ask questions! | |
| ## More details | |
| The [plugin chapter in the contributor book](/contributor-book/plugins.md) offers more details on the intricacies of how plugins work from a software developer point of view. | |