# Standard Input

The **stdin** plugin allows to retrieve valid JSON text messages over the standard input interface (stdin). In order to use it, specify the plugin name as the input, e.g:

```bash
$ fluent-bit -i stdin -o stdout
```

As input data the *stdin* plugin recognize the following JSON data formats:

```bash
1. { map => val, map => val, map => val }
2. [ time, { map => val, map => val, map => val } ]
```

A better example to demonstrate how it works will be through a *Bash* script that generates messages and writes them to [Fluent Bit](http://fluentbit.io). Write the following content in a file named *test.sh*:

```bash
#!/bin/sh

while :; do
  echo -n "{\"key\": \"some value\"}"
  sleep 1
done
```

Give the script execution permission:

```bash
$ chmod 755 test.sh
```

Now lets start the script and [Fluent Bit](http://fluentbit.io) in the following way:

```bash
$ ./test.sh | fluent-bit -i stdin -o stdout
Fluent Bit v1.x.x
* Copyright (C) 2019-2020 The Fluent Bit Authors
* Copyright (C) 2015-2018 Treasure Data
* Fluent Bit is a CNCF sub-project under the umbrella of Fluentd
* https://fluentbit.io

[2016/10/07 21:44:46] [ info] [engine] started
[0] stdin.0: [1475898286, {"key"=>"some value"}]
[1] stdin.0: [1475898287, {"key"=>"some value"}]
[2] stdin.0: [1475898288, {"key"=>"some value"}]
[3] stdin.0: [1475898289, {"key"=>"some value"}]
[4] stdin.0: [1475898290, {"key"=>"some value"}]
```

## Configuration Parameters <a href="#config" id="config"></a>

The plugin supports the following configuration parameters:

| Key          | Description                                                                                                                                                                                                                        | Default |
| ------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------- |
| Buffer\_Size | Set the buffer size to read data. This value is used to increase buffer size. The value must be according to the [Unit Size](https://docs.fluentbit.io/manual/2.0/administration/configuring-fluent-bit/unit-sizes) specification. | 16k     |


---

# 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://docs.fluentbit.io/manual/2.0/pipeline/inputs/standard-input.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.