> For the complete documentation index, see [llms.txt](https://hub.bsvblockchain.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hub.bsvblockchain.org/higher-learning/bsv-academy/bsv-opcodes/stack-operations.md). # Stack Operations Bitcoin Script's power comes from its ability to manipulate data efficiently. Unlike traditional programming where you work with named variables, **Bitcoin Script uses a stack**—a last-in-first-out data structure where **items are pushed onto the top and popped from the top**. Understanding how to rearrange, copy, and remove items from this stack is fundamental to writing effective Bitcoin scripts. Stack operations are the building blocks that **allow scripts to organize data for validation**. Whether you're building a simple payment script or a complex multi-party contract, you'll constantly use these opcodes to position values where they're needed for computation, comparison, or signature verification. {% embed url="" %} #### You will explore: * How stack duplicators create copies of data without altering originals * When to eliminate unnecessary values to keep scripts efficient * How relocators rearrange stack items for computation * The role of the alternate stack in complex operations * Practical patterns combining stack operations #### By the end of this chapter, learners will: * Understand the three categories of stack operations and their purposes * Apply duplicators to preserve values for multiple operations * Construct scripts that efficiently manage stack depth * Implement alternate stack patterns for temporary storage --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://hub.bsvblockchain.org/higher-learning/bsv-academy/bsv-opcodes/stack-operations.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. 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.