feat: Add __main_target path verification

src/lib/source.sh

@@ -68,6 +68,15 @@ validate_targets() {
         # Set __main_target. This variable contains path to save local backups.
         # Files to additional targets will be coped from this directory.
         __main_target="${file_targets[0]}"
+        # Fail if __main_target's path is not a directory
+        parse_uri "$__main_target"
+        if [ -d "$path" ]; then
+            __main_target="$path"
+        else
+            echo "Error: Path $path in $__main_target" \
+                "is not directory or does not exists" >&2
+            exit 1
+        fi
     fi
 }