# `openagent` - Command Reference

> 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

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