# Define Handlers For "`open`" (`openagent`)

> Creates a handler function for `open`

## Description

`openagent` creates and destroys handler functions for writing data to the
terminal when accessed via `open` and stdout is a TTY.

## Usage

Display code block for an associated data-type:

```
openagent get data-type
```

Define an `open` handler function:

```
openagent set data-type { code-block }
```

Undefine an `open` handler:

```
!openagent data-type
```

## Detail

### FileRef

It is possible to track which shell script or module installed what `open`
handler by checking `runtime --open-agents` and checking it's **FileRef**.

## Synonyms

* `openagent`
* `!openagent`


## See Also

* [Execute Function or Builtin: `fexec`](../commands/fexec.md):
  Execute a command or function, bypassing the usual order of precedence.
* [FileRef](../user-guide/fileref.md):
  How to track what code was loaded and from where
* [Modules And Packages](../user-guide/modules.md):
  Modules and packages: An Introduction
* [Open File: `open`](../commands/open.md):
  Open a file with a preferred handler
* [Shell Runtime: `runtime`](../commands/runtime.md):
  Returns runtime information on the internal state of Murex

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This document was generated from [builtins/core/open/open_doc.yaml](https://github.com/lmorg/murex/blob/master/builtins/core/open/open_doc.yaml).