wiki: add manual update guide for Gemini CLI

03-opensource/productivity/rmlint-duplicate-scanning.md

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+# rmlint — Extreme Duplicate File Scanning
+
+## Problem
+
+Over time, backups and media collections can accumulate massive amounts of duplicate data. Traditional duplicate finders are often slow and limited in how they handle results. On MajorRAID, I identified **~4.0 TB (113,584 files)** of duplicate data across three different storage points.
+
+## Solution
+
+`rmlint` is an extremely fast tool for finding (and optionally removing) duplicates. It is significantly faster than `fdupes` or `rdfind` because it uses a multi-stage approach to avoid unnecessary hashing.
+
+### 1. Installation (Fedora)
+
+```bash
+sudo dnf install rmlint
+```
+
+### 2. Scanning Multiple Directories
+
+To scan for duplicates across multiple mount points and compare them:
+
+```bash
+rmlint /majorstorage /majorRAID /mnt/usb
+```
+
+This will generate a script named `rmlint.sh` and a summary of the findings.
+
+### 3. Reviewing Results
+
+**DO NOT** run the generated script without reviewing it first. You can use the summary to see which paths contain the most duplicates:
+
+```bash
+# View the summary
+cat rmlint.json | jq .
+```
+
+### 4. Advanced Usage: Finding Duplicates by Hash Only
+
+If you suspect duplicates with different filenames:
+
+```bash
+rmlint --hidden --hard-links /path/to/search
+```
+
+### 5. Repurposing Storage
+
+After scanning and clearing duplicates, you can reclaim significant space. In my case, this was the first step in repurposing a 12TB USB drive as a **SnapRAID parity drive**.
+
+---
+
+## Maintenance
+
+Run a scan monthly or before any major storage consolidation project.
+
+---
+
+## Tags
+
+#rmlint #linux #storage #cleanup #duplicates