---
id: "prereq-unix-pipelines"
type: "prereq"
source_timestamps: ["§2.1"]
tags: ["lineage", "unix"]
related: ["concept-icm", "concept-icm-as-compilation"]
sources: ["paper"]
sourceVaultSlug: "icm-paper-folder-architecture-2026Jun02"
originDay: 2
---
# Unix pipelines and the pipe-and-filter pattern

## Why this is a prerequisite

ICM is the **Unix philosophy applied to AI agents**:

- *Do one thing well* (McIlroy),
- *Plain text as universal interface*,
- *Human-readable intermediate state*.

## Key sources

- **McIlroy** — "Do one thing well."
- **Shaw & Garlan** — the pipe-and-filter architectural pattern.

## What understanding this enables

The principles that made Unix pipelines effective are the *same* principles that make ICM work for sequential agent workflows. Stages are filters; folders are pipes; markdown files are the plain-text universal interface.

This prerequisite also feeds the more elaborated theoretical analogy in [[concept-icm-as-compilation]] (multi-pass compilation), which extends pipe-and-filter to incremental re-runs and intermediate-representation inspection.


## Related across days
- [[prereq-markdown]]
- [[concept-icm-as-compilation]]
- [[concept-icm-d2]]