diff --git a/SC2039.md b/SC2039.md
index df73ca8..cb7eb95 100644
--- a/SC2039.md
+++ b/SC2039.md
@@ -42,6 +42,10 @@ eval_gettext 'foo $barout baz' # See GNU Gettext doc for more info.
 
 Or you can change them to normal double quotes so you go without `gettext`.
 
+### `${var:1}` (substring expansion)
+
+https://wiki.ubuntu.com/DashAsBinSh#A.24.7Bfoo:3.5B:1.5D.7D
+
 ### Arithmetic `for` loops
 
 Bash: