python plugin installer script - narrative comments

Author: d-w-moore

irods/test/harness/install_python_rule_engine

@@ -2,22 +2,31 @@
 
 python_rule_plugin_package_spec() {
   local PKG=irods-rule-engine-plugin-python
+
+  # Grep pattern to filter plugin package names for those compatible with the target version of iRODS.
   local search_str="+$IRODS_PACKAGE_VERSION"
   if [ "$1" = "all" ]; then
     search_str=""
   fi
+
+  # Collect available version strings for the plugin for our iRODS server version.
   local VERSIONS=$(apt list -a $PKG 2>/dev/null|\
                    awk '{print $2}'|\
                    grep '\w'|\
                    grep "$(
                       perl -e 'print quotemeta($ARGV[0])' "$search_str")"
                   )
+
+  # Get the highest version number among the list in $VERSIONS
   local LATEST_VERSION=$(sort -V <<<"$VERSIONS" | tail -1)
+
   if [ "$1" = "latest" ]; then
+      # Output the appropriate format for apt install targets
       echo "$PKG=$LATEST_VERSION"
   else
       echo "$VERSIONS"
  fi
 }
 
+# Download/install the latest Python Rule Engine plugin appropriate for the iRODS server we have installed.
 apt install -y "$(python_rule_plugin_package_spec latest)"