| # Plugins |
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| 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. |
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| 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. |
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| ## Adding a plugin |
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| 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. |
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| Please note that the plugin name needs to start with `nu_plugin_`, Nu uses the name prefix to detect plugins. |
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| Linux+macOS: |
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| ```nu |
| > register ./my_plugins/nu_plugin_cool |
| ``` |
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| Windows: |
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| ```nu |
| > register .\my_plugins\nu_plugin_cool.exe |
| ``` |
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| When [`register`](/commands/docs/register.md) is called: |
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| 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 |
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| Once registered, the plugin is available as part of your set of commands: |
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| ```nu |
| > help commands | where command_type == "plugin" |
| ``` |
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| ## Examples |
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| Nu's main repo contains example plugins that are useful for learning how the plugin protocol works: |
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| - [Rust](https://github.com/nushell/nushell/tree/main/crates/nu_plugin_example) |
| - [Python](https://github.com/nushell/nushell/blob/main/crates/nu_plugin_python) |
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| ## Debugging |
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| 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. |
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| ## Help |
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| 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! |
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| ## More details |
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| 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. |
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