diff --git a/distribusi/test.py b/distribusi/test.py
index 0a9e81f..7d5f46e 100644
--- a/distribusi/test.py
+++ b/distribusi/test.py
@@ -2,14 +2,18 @@
 # 2020. 10. 26
 from distribusi.cli import build_argparser, distribusify
 from distribusi import fragments
+from filelock import Timeout, FileLock
 
-parser = build_argparser()
-args = parser.parse_args()
+lock = FileLock("./data/.lock")
 
-data_path = args.directory
+with lock:
+    parser = build_argparser()
+    args = parser.parse_args()
 
-freg = fragments.Fragments()
-freg.preindex(data_path)
-freg.postindex()
+    data_path = args.directory
 
-distribusify(args, data_path, freg)
+    freg = fragments.Fragments()
+    freg.preindex(data_path)
+    freg.postindex()
+
+    distribusify(args, data_path, freg)
diff --git a/poetry.lock b/poetry.lock
index 8d5f26b..e381c11 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -1,3 +1,11 @@
+[[package]]
+name = "filelock"
+version = "3.0.12"
+description = "A platform independent file lock."
+category = "main"
+optional = false
+python-versions = "*"
+
 [[package]]
 name = "markdown"
 version = "3.3.4"
@@ -28,9 +36,13 @@ python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.8"
-content-hash = "e17d31e9ee7949d99baf929cdd55b9565284dbe08e81d3cb7691f58cb5a04c74"
+content-hash = "2122e4cf5f141d6098cc17000ce0ab06dc0caabd0f43e92c3dc7cd88f67b5934"
 
 [metadata.files]
+filelock = [
+    {file = "filelock-3.0.12-py3-none-any.whl", hash = "sha256:929b7d63ec5b7d6b71b0fa5ac14e030b3f70b75747cef1b10da9b879fef15836"},
+    {file = "filelock-3.0.12.tar.gz", hash = "sha256:18d82244ee114f543149c66a6e0c14e9c4f8a1044b5cdaadd0f82159d6a6ff59"},
+]
 markdown = [
     {file = "Markdown-3.3.4-py3-none-any.whl", hash = "sha256:96c3ba1261de2f7547b46a00ea8463832c921d3f9d6aba3f255a6f71386db20c"},
     {file = "Markdown-3.3.4.tar.gz", hash = "sha256:31b5b491868dcc87d6c24b7e3d19a0d730d59d3e46f4eea6430a321bed387a49"},
diff --git a/pyproject.toml b/pyproject.toml
index 5d7bc4c..e0d6650 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -9,6 +9,7 @@ python = "^3.8"
 Pillow = "^8.3.1"
 python-magic = "^0.4.24"
 Markdown = "^3.3.4"
+filelock = "^3.0.12"
 
 [tool.poetry.dev-dependencies]