> ## Documentation Index
> Fetch the complete documentation index at: https://e2b.manicule.dev/llms.txt
> Use this file to discover all available pages before exploring further.
> For every page in one file, fetch https://e2b.manicule.dev/llms-full.txt (large).
> To search and read these docs as tools, connect the MCP server at https://e2b.manicule.dev/api/mcp.
> Every agent surface: https://e2b.manicule.dev/.well-known/llms-manifest.json

# Streaming command output (/docs/commands/streaming)

<!-- agent-signals: reading_time_min: 1 · est_tokens: 200 · updated: 2026-07-30 -->
Related: [Running commands in background](/docs/commands/background.md), [Available servers](/docs/mcp/available-servers.md)

To stream command output as it is being executed, pass the `onStdout`, `onStderr` callbacks to the `commands.run()` method in JavaScript
or the `on_stdout`, `on_stderr` callbacks to the `commands.run()` method in Python.

<CodeGroup>
```js title="JavaScript & TypeScript"
import { Sandbox } from 'e2b'

const sandbox = await Sandbox.create()

const result = await sandbox.commands.run('echo hello; sleep 1; echo world', {
  onStdout: (data) => {
    console.log(data)
  },
  onStderr: (data) => {
    console.log(data)
  },
})
console.log(result)
```

```python title="Python"
from e2b import Sandbox

sandbox = Sandbox.create()

result = sandbox.commands.run('echo hello; sleep 1; echo world', on_stdout=lambda data: print(data), on_stderr=lambda data: print(data))
print(result)
```
</CodeGroup>