Add documentation

README.md

@@ -1,3 +1,37 @@
 # upgrade_debian_iso
 
-Upgrade debian iso with jigdo.
+Upgrade a provided debian iso with jigdo to last minor release.
+
+## Requirements
+
+A (recent) debian host.
+Install the packages jigdo-file wget and udisks2 on it.
+Execute the script on a physical console (not ssh) to avoid polkit issues.
+
+## Usage
+
+Adapt the config file **release-name**-**architecture**.txt to your case.
+
+```bash
+http_proxy=http://192.168.0.253:3142/
+ISOFILE=$HOME/debian-12.12.0-i386-netinst.iso
+JIGDO=$HOME/jigdo
+DESTINATION=$HOME
+MIRROR=http://debian.proxad.net
+MIRRORNONUS=http://debian.proxad.net
+```
+
+Set or remove http_proxy if you have one (like apt-cacher-ng).
+
+Set the (old) isofile path of the same release and architecture you have.
+
+Set the paths you want and a specific mirror if you want.
+
+```bash
+$ bash upgrade.sh --configfile bookworm_i386.txt
+...
+```
+
+It will upgrade the packages of the old medium file and generate a isofile in the last revision, the same as provided with a direct download.
+
+You can burn it, copy it or use it the same as a downloaded netinst file.

upgrade.sh

@@ -7,7 +7,7 @@ check_tools()
 {
     if ! udisksctl status >/dev/null
     then 
-        echo "udisksctl is required"
+        echo "udisks2 is required"
         exit 1
     fi
     if ! wget --version >/dev/null
@@ -17,7 +17,7 @@ check_tools()
     fi
     if ! jigdo-lite --version >/dev/null
     then
-        echo "jigdo-lite is required"
+        echo "jigdo-file is required"
         exit 1
     fi
 }