diff --git a/filetags.py b/filetags.py
index 4a87c8d..cf1dd08 100644
--- a/filetags.py
+++ b/filetags.py
@@ -344,9 +344,11 @@ if __name__ == "__main__":
   # lookup subcommand: return hash and tags of found files
   # arguments: <storage directory> <hash|exact tag|set of exact tags>
   # modifiers:
-  #  first - only return one file
+  #  first   - only return one file
   #  unique - return error if not found or multiple found
-  #TODO: modifiers
+  #  hash   - perform lookup by hash
+  #  tags   - perform lookup by tag or set of tags
+  #TODO: modifiers: first unique
   if command[0] == "lookup":
     if len(sys.argv)<4:
       print("Too few arguments!", file=sys.stderr)
@@ -363,28 +365,30 @@ if __name__ == "__main__":
         print("Verifying container settings failed.", file=sys.stderr)
       sys.exit(status)
 
-    file_tags_or_hash = sys.argv[3:]
-    if file_is_in_storage(storage_directory, file_tags_or_hash[0], compress):
-      tags = get_tags_by_hash(storage_directory, file_tags_or_hash[0])
-      print("Tags for file:")
-      print(tags)
+    if not 'tags' in command:
+      file_tags_or_hash = sys.argv[3:]
+      if file_is_in_storage(storage_directory, file_tags_or_hash[0], compress):
+        tags = get_tags_by_hash(storage_directory, file_tags_or_hash[0])
+        print("Tags for file:")
+        print(tags)
 
-    # create a two dimensional array of all the files associated with each individual tag
-    file_hash_lists = []
-    for tag in file_tags_or_hash:
-      file_hash_lists = file_hash_lists + [get_hashes_by_tag(storage_directory, tag)]
-    # take the first of the arrays in the two dimensional array
-    common_file_hashes = file_hash_lists[0]
-    # iterate over the two dimensional array
-    for file_hash_list in file_hash_lists:
-      # check each element in common_file_hashes to ensure it is also in all other arrays in the two dimensional array, remove if it isn’t
-      for file_hash in common_file_hashes:
-        if not file_hash in file_hash_list:
-          common_file_hashes.remove(file_hash)
+    if not 'hash' in command:
+      # create a two dimensional array of all the files associated with each individual tag
+      file_hash_lists = []
+      for tag in file_tags_or_hash:
+        file_hash_lists = file_hash_lists + [get_hashes_by_tag(storage_directory, tag)]
+      # take the first of the arrays in the two dimensional array
+      common_file_hashes = file_hash_lists[0]
+      # iterate over the two dimensional array
+      for file_hash_list in file_hash_lists:
+        # check each element in common_file_hashes to ensure it is also in all other arrays in the two dimensional array, remove if it isn’t
+        for file_hash in common_file_hashes:
+          if not file_hash in file_hash_list:
+            common_file_hashes.remove(file_hash)
 
-    if not common_file_hashes == []:
-      print("Files for tag(s):")
-      print(common_file_hashes)
+      if not common_file_hashes == []:
+        print("Files for tag(s):")
+        print(common_file_hashes)