Added minor changes (documentation) and indentation for readability.

Readme correct referencing to new docs directory its file.
    couple comments and indentations to improve readability.
    Added a dummy Ubuntu 22 and MacOS categories as an example.

README.md

@@ -102,14 +102,10 @@ The tasks you want to run should be contained under the `tasks:` with two fields
 The name field is for the user of meshbook, to clarify what the following command does in a summary.<br>
 The command field actually gets executed on the end-point.<br>
 
-### Granual Operating System control:
+### Granual Operating System filtering:
 
-I have made the program so it can have a basic filter with the Operating systems. If you have a mixed group, then you need to match the image below like this:
-
-<img src="./assets/meshcentral_os.png" alt="MeshCentral Operating System Version" width="600"/><br>
-<img src="./assets/meshbook_yaml_os.png" alt="MeshBook yaml example" width="600"/>
-
-This will filter the nodes/machines in the MeshCentral group to the ones matching this. Very basic and open for feedback. This must match the full string, not case sensitive.
+I have made the program so it can have a filter with the Operating systems. If you have a mixed group, please read:
+[This explanation](./docs/operating_system_filtering.md)
 
 # Example:
 

meshbook.py

@@ -101,6 +101,7 @@ async def filter_targets(devices: list[dict], os_categories: dict, target_os: st
 
     def get_os_variants(category: str, os_map: dict) -> set:
         """Extracts all OS names under a given category if it exists."""
+
         for key, value in os_map.items():
             if key == category:
                 if isinstance(value, dict):  # Expand nested categories
@@ -124,6 +125,7 @@ async def filter_targets(devices: list[dict], os_categories: dict, target_os: st
             allowed_os = get_os_variants(target_os, os_categories[key])
             break  # Stop searching once a match is found
 
+    # Filter out unreachable devices
     for device in devices:
         if not device["reachable"]:
             continue  # Skip unreachable devices.

os_categories.json

@@ -6,6 +6,9 @@
         ],
         "Ubuntu": [
             "Ubuntu 24.04.1 LTS"
+        ],
+        "Ubuntu 22": [
+            "Ubuntu 22.04.1 LTS"
         ]
     },
     "MacOS": {