Move docs into wiki/ with GitHub Action sync

- Rename docs/ to wiki/ — source of truth for wiki content
- Add wiki/Home.md as the wiki landing page with navigation
- Add .github/workflows/sync-wiki.yml to auto-publish wiki/
  to the GitHub wiki on push to master
- Update README.md links to wiki/ directory

The wiki at github.com/firehol/iprange/wiki is now a mirror of
the wiki/ directory in this repo. Edit wiki/ in the repo, and
the GitHub Action syncs it to the wiki on merge to master.

Author: ktsaou

.github/workflows/sync-wiki.yml

@@ -0,0 +1,37 @@
+name: Sync wiki
+
+on:
+  push:
+    branches: [master]
+    paths:
+      - 'wiki/**'
+
+jobs:
+  sync:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v4
+
+      - name: Checkout wiki
+        uses: actions/checkout@v4
+        with:
+          repository: ${{ github.repository }}.wiki
+          path: wiki-repo
+          token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Sync wiki files
+        run: |
+          cp wiki/*.md wiki-repo/
+          cd wiki-repo
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+          git add -A
+          if git diff --cached --quiet; then
+            echo "No wiki changes to sync"
+          else
+            git commit -m "Sync wiki from repo"
+            git push
+          fi

README.md

@@ -366,7 +366,7 @@ To skip the man page: `./configure --disable-man`
 | Directory | Contents |
 |-----------|----------|
 | `src/` | C sources and headers |
-| `docs/` | Detailed documentation |
+| `wiki/` | Documentation (synced to GitHub wiki) |
 | `packaging/` | Spec template, ebuild, release tooling |
 | `tests.d/` | CLI regression tests |
 | `tests.build.d/` | Build and layout regressions |
@@ -376,14 +376,14 @@ To skip the man page: `./configure --disable-man`
 
 ## Documentation
 
-Detailed guides in the [`docs/`](docs/) directory:
+Detailed guides in the [`wiki/`](wiki/) directory (also published to the [GitHub wiki](https://github.com/firehol/iprange/wiki)):
 
-- [Input formats](docs/input-formats.md) — every accepted format, file lists, directories, binary
-- [Output formats](docs/output-formats.md) — CIDR, ranges, single IPs, binary, CSV, prefix/suffix
-- [Operations](docs/operations.md) — merge, intersect, exclude, diff, reduce, compare, count
-- [IPv6 support](docs/ipv6.md) — address family, normalization, cross-family rules
-- [DNS resolution](docs/dns-resolution.md) — threading, retry, configuration
-- [Optimizing ipsets for iptables](docs/ipset-reduce.md) — prefix reduction with examples
+- [Input formats](wiki/input-formats.md) — every accepted format, file lists, directories, binary
+- [Output formats](wiki/output-formats.md) — CIDR, ranges, single IPs, binary, CSV, prefix/suffix
+- [Operations](wiki/operations.md) — merge, intersect, exclude, diff, reduce, compare, count
+- [IPv6 support](wiki/ipv6.md) — address family, normalization, cross-family rules
+- [DNS resolution](wiki/dns-resolution.md) — threading, retry, configuration
+- [Optimizing ipsets for iptables](wiki/ipset-reduce.md) — prefix reduction with examples
 
 ## Getting help
 

wiki/Home.md

@@ -0,0 +1,69 @@
+# iprange
+
+`iprange` is a fast command-line tool for managing IPv4 and IPv6 address sets. It reads IPs, CIDRs, ranges, and hostnames, normalizes them into optimal non-overlapping sets, and performs set operations: union, intersection, difference, complement, comparison, and prefix reduction.
+
+For 1 million input lines, a merge completes in under a second.
+
+## Documentation
+
+- [Input formats](input-formats.md) — every accepted format, file lists, directories, binary input
+- [Output formats](output-formats.md) — CIDR, ranges, single IPs, binary, CSV, prefix/suffix strings
+- [Operations](operations.md) — merge, intersect, exclude, diff, reduce, compare, count
+- [IPv6 support](ipv6.md) — address family selection, normalization, cross-family rules
+- [DNS resolution](dns-resolution.md) — parallel threading, retry, configuration
+- [Optimizing ipsets for iptables](ipset-reduce.md) — prefix reduction tutorial with examples
+
+## Quick reference
+
+```
+iprange [options] file1 file2 ...
+```
+
+### Address family
+
+| Flag | Mode |
+|------|------|
+| *(default)* | IPv4 |
+| `-4` / `--ipv4` | Explicit IPv4 |
+| `-6` / `--ipv6` | IPv6 (accepts both IPv6 and IPv4, normalizes IPv4 to `::ffff:x.x.x.x`) |
+
+### Operations
+
+| Option | Operation | Output |
+|--------|-----------|--------|
+| *(default)* | Union / merge | CIDR |
+| `--common` | Intersection | CIDR |
+| `--except` | A minus B (positional) | CIDR |
+| `--diff` | Symmetric difference (positional) | CIDR |
+| `--ipset-reduce N` | Merge + reduce prefixes | CIDR |
+| `--compare` | All vs all | CSV |
+| `--compare-first` | First vs rest | CSV |
+| `--compare-next` | Group vs group (positional) | CSV |
+| `--count-unique` / `-C` | Merged counts | CSV |
+| `--count-unique-all` | Per-file counts | CSV |
+
+### Output format
+
+| Option | Format |
+|--------|--------|
+| *(default)* | CIDR (`10.0.0.0/24`) |
+| `-j` / `--print-ranges` | Ranges (`10.0.0.0-10.0.0.255`) |
+| `-1` / `--print-single-ips` | One IP per line |
+| `--print-binary` | Binary (same-architecture cache) |
+
+### Feature detection
+
+```bash
+iprange --has-compare           # compare modes
+iprange --has-reduce            # reduce mode
+iprange --has-filelist-loading  # @filename support
+iprange --has-directory-loading # @directory support
+iprange --has-ipv6              # IPv6 support
+```
+
+Each exits 0 if the feature is present.
+
+## Related projects
+
+- [FireHOL IP Lists](https://iplists.firehol.org) — curated collection of IP blocklists, updated daily using `iprange`
+- [FireHOL](https://github.com/firehol/firehol) — Linux firewall tool that uses `iprange` for ipset management