Debian packaging

README.md

@@ -139,6 +139,55 @@ From then on, `sudo dnf upgrade` picks up new releases.
 - The RPM is built against this machine's libraries, so it installs on this
   Fedora release and newer.
 
+### Distributing to Debian/Ubuntu (apt repo)
+
+Debian-based machines get the app the same way, from an apt repo you host.
+`scripts/deb-publish.sh` builds the `.deb` here on Fedora and adds it to the
+repo in a directory you choose. It needs:
+
+```bash
+sudo dnf install reprepro dpkg
+```
+
+It signs with the same key as the dnf repo. If you haven't made that key yet,
+pass `--init-key` the first time. Either way, give the first run the address
+the directory will be served at:
+
+```bash
+DEB_REPO_URL=https://deb.example.com/mtgc ./scripts/deb-publish.sh ~/deb-mtgc
+```
+
+After that, publishing is just:
+
+```bash
+./scripts/deb-publish.sh ~/deb-mtgc     # or: npm run deb:publish -- ~/deb-mtgc
+```
+
+Then, on each machine, add the repo once and install:
+
+```bash
+sudo curl -fsSLo /etc/apt/sources.list.d/mtgc.sources https://deb.example.com/mtgc/mtgc.sources
+```
+
+```bash
+sudo apt update && sudo apt install mtgc
+```
+
+From then on, `sudo apt upgrade` picks up new releases.
+
+- **Serve the whole directory.** It holds `pool/`, the signed `dists/`, the
+  public key (`mtgc.asc`) and `mtgc.sources`, which carries the key inline so
+  machines don't need a separate keyring step. `conf/` and `db/` are
+  reprepro's own state; they're harmless to serve but aren't needed. The
+  newest three versions are kept, so a bad release can be undone with
+  `sudo apt install mtgc=<older version>`.
+- Versions are the same as the RPM's. A build published with `--allow-dirty`
+  gets a `~dirty` suffix, which apt sorts below the clean build of the same
+  version.
+- The `.deb` is built against this machine's libraries, so it needs a distro
+  with at least this Fedora's glibc (2.43 on Fedora 44). Older Debian and
+  Ubuntu releases can't install it.
+
 ### Distributing to Windows
 
 The Windows installer is cross-built here on Linux and published to a plain