# Copy

> Reference for file copy operations: duplication, rsync patterns, copy-on-write, buffer strategies, and cross-platform sync.

- Skill: `luokai0/copy` (Agent Skill, multi-file: 4 files)
- Install (CLI): `npx skillmds@latest add luokai0/copy`
- Raw SKILL.md: https://api.skillmd.com/api/skills/luokai0/copy/raw
- Safety review: CAUTION (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: DevOps & Infra, AI & ML
- Tags: Backup, Copy On Write, Data Transfer, File Copy, File Sync, Rsync
- Author: luokai0 (https://skillmd.com/u/luokai0)
- Updated: 2026-08-22
- Page: https://skillmd.com/skills/luokai0/copy

---


# Copy — File & Data Copy Operations Reference

Quick-reference skill for file copy strategies, rsync patterns, copy-on-write, and cross-platform synchronization.

## When to Use

- Duplicating files or directory trees with specific filters
- Setting up rsync-based backups or mirrors
- Understanding copy-on-write (CoW) behavior
- Implementing efficient copy strategies for large datasets
- Troubleshooting copy failures and permission issues

## Commands

### `intro`

```bash
scripts/script.sh intro
```

Overview of copy operations — types, semantics, and platform differences.

### `rsync`

```bash
scripts/script.sh rsync
```

Rsync patterns — common flags, partial transfers, and include/exclude rules.

### `cow`

```bash
scripts/script.sh cow
```

Copy-on-Write (CoW) — reflinks, filesystem support, and when to use.

### `patterns`

```bash
scripts/script.sh patterns
```

Common copy patterns — mirroring, incremental, differential, snapshot.

### `filters`

```bash
scripts/script.sh filters
```

File filtering techniques — by extension, date, size, and gitignore integration.

### `performance`

```bash
scripts/script.sh performance
```

Performance optimization — buffer sizes, parallel copy, and I/O tuning.

### `errors`

```bash
scripts/script.sh errors
```

Common copy errors, permissions issues, and troubleshooting guide.

### `checklist`

```bash
scripts/script.sh checklist
```

Pre-copy and post-copy verification checklist.

### `help`

```bash
scripts/script.sh help
```

### `version`

```bash
scripts/script.sh version
```

## Configuration

| Variable | Description |
|----------|-------------|
| `COPY_DIR` | Data directory (default: ~/.copy/) |

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