diff --git a/aider/coders/editblock_coder.py b/aider/coders/editblock_coder.py
index 9b922f9f1..f350d28b5 100644
--- a/aider/coders/editblock_coder.py
+++ b/aider/coders/editblock_coder.py
@@ -429,7 +429,6 @@ def find_original_update_blocks(content, fence=DEFAULT_FENCE):
             "```tcsh",
         ]
         if any(line.strip().startswith(start) for start in shell_starts):
-            shell_type = line.strip().split("```")[1]
             shell_content = []
             i += 1
             while i < len(lines) and not lines[i].strip().startswith("```"):