Created SC2231 (markdown)

SC2231.md

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+## Quote expansions in this for loop glob to prevent wordsplitting, e.g. "$dir"/*.txt .
+
+### Problematic code:
+
+```sh
+for file in $dir/*.txt
+do
+  echo "Found $file"
+done
+```
+
+### Correct code:
+
+```sh
+for file in "$dir"/*.txt
+do
+  echo "Found $file"
+done
+```
+
+### Rationale:
+
+When iterating over globs containing expansions, you can still quote all expansions in the path to better handle whitespace and special characters.
+
+Just make sure glob characters are outside quotes. `"$dir/*.txt"` will not glob expand, but `"$dir"/*.txt` or `"$dir"/*."$ext"` will. 
+
+### Exceptions:
+
+Exceptions similar to [[SC2086]] apply. If the variable is expected to contain globs, such as if `dir="tmp/**"` in the example, you can ignore this message.
+
+### Related resources:
+
+* Help by adding links to BashFAQ, StackOverflow, man pages, POSIX, etc!