diff --git a/Build/tools-dedupe-src.ts b/Build/tools-dedupe-src.ts
new file mode 100644
index 00000000..c1fc6191
--- /dev/null
+++ b/Build/tools-dedupe-src.ts
@@ -0,0 +1,45 @@
+import { fdir as Fdir } from 'fdir';
+import path from 'node:path';
+import fsp from 'node:fs/promises';
+import { SOURCE_DIR } from './constants/dir';
+import { readFileByLine } from './lib/fetch-text-by-line';
+
+(async () => {
+  const files = await new Fdir()
+    .withFullPaths()
+    .filter((filepath, isDirectory) => {
+      if (isDirectory) return true;
+
+      const extname = path.extname(filepath);
+
+      return extname !== '.js' && extname !== '.ts';
+    })
+    .crawl(SOURCE_DIR)
+    .withPromise();
+
+  await Promise.all(files.map(dedupeFile));
+})();
+
+async function dedupeFile(file: string) {
+  const set = new Set<string>();
+  const result: string[] = [];
+
+  for await (const line of readFileByLine(file)) {
+    if (line.length === 0) {
+      result.push(line);
+      continue;
+    }
+    if (line[0] === '#') {
+      result.push(line);
+      continue;
+    }
+    if (set.has(line)) {
+      // do nothing
+    } else {
+      set.add(line);
+      result.push(line);
+    }
+  }
+
+  return fsp.writeFile(file, result.join('\n') + '\n');
+}