Add file tracking status query function

src/package/package_tracking.sh

@@ -1,8 +1,26 @@
+# functions to track, untrack and query tracked state of packages
+
+# returns 0 if all packages are tracked, 1 if any is untracked
+query_packages() {
+  local packages="$1"
+
+  echo "$packages" | xargs | sed 's/ /\n/g' | while read -r package; do
+    if ! cat "$CONFIG_ROOT/packages" | grep -q "^$package$"; then
+      return 1
+    fi
+    return 0
+  done
+}
+
 track_packages() {
   local packages="$1"
 
   echo "$packages" | xargs | sed 's/ /\n/g' | while read -r package; do
+    if query_packages "$package"; then
+      log info "Package $package was not tracked because it is already tracked"
+    else
       echo "$package" >> "$CONFIG_ROOT/packages"
+    fi
   done
 }