diff --git a/aider/utils.py b/aider/utils.py
index 1b9873b4b..9164c156b 100644
--- a/aider/utils.py
+++ b/aider/utils.py
@@ -118,8 +118,11 @@ def quoted_file(fname, display_fname):
     prompt = "\n"
     prompt += display_fname
     prompt += "\n```\n"
-    prompt += Path(fname).read_text()
-    prompt += "\n```\n"
+    file_content = Path(fname).read_text()
+    lines = file_content.splitlines()
+    for i, line in enumerate(lines, start=1):
+        prompt += f"{i:3d} {line}\n"
+    prompt += "```\n"
     return prompt