diff --git a/__main__.py b/__main__.py
new file mode 100755
index 0000000..7e4e799
--- /dev/null
+++ b/__main__.py
@@ -0,0 +1,29 @@
+#! /usr/bin/env python3
+
+import subprocess
+import sys
+
+
+def bootstrap():
+    pass
+
+
+def squash(input_root):
+    subprocess.call([
+        'mksquashfs',
+        input_root,
+        ?,
+        '-comp', 'zstd',
+        '-Xcompression-level', str(18),
+    ])
+
+
+def main():
+    _, output_root = sys.argv
+    bootstrap()
+    squash()
+    print('ok')
+
+
+if __name__ == '__main__':
+    main()