> For the complete documentation index, see [llms.txt](https://karansingh.gitbook.io/aws-saa-c02/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://karansingh.gitbook.io/aws-saa-c02/ec2/user-data.md).

# User Data

* User data can be used to **perform common automated configuration tasks** and even **run scripts** after the instance start&#x73;**.**<br>
* In computing, a **bootstrap loader is the first piece of code that runs when a machine starts**.<br>
* It is **not very secure** as anyone who has access to the operating system can have access to the User Data, so you **shouldn't use it for storing anything sensitive** or personal, like passwords.