diff --git a/git-diffall b/git-diffall
index 84f2b65..c0e5d0b 100755
--- a/git-diffall
+++ b/git-diffall
@@ -252,6 +252,18 @@ then
 	find "$tmp/$right_dir" -type f |
 	while read file
 	do
-		cp "$file" "$git_top_dir/${file#$tmp/$right_dir/}"
+		copy_target="$git_top_dir/${file#$tmp/$right_dir/}"
+		if test -f "$copy_target"
+		then 
+			diff -p "$copy_target" "$file"
+			should_cp=$?
+		else
+			echo "copy-back: $copy_target: Missing file is copied back"
+			should_cp=1
+		fi
+		if test $should_cp -ne 0 
+		then
+			cp "$file" "$copy_target"
+		fi
 	done
 fi