diff --git a/runtime/syntax/sh.yaml b/runtime/syntax/sh.yaml
index 5471e7ad..54268269 100644
--- a/runtime/syntax/sh.yaml
+++ b/runtime/syntax/sh.yaml
@@ -20,8 +20,8 @@ rules:
     - statement: "--[a-z-]+"
     - statement: "\\ -[a-z]+"
 
-    - identifier: "\\$\\{?[0-9A-Z_!@#$*?-]+\\}?"
-    - identifier: "\\$\\{?[0-9A-Z_!@#$*?-]+\\}?"
+    - identifier: "\\$\\{?[0-9A-Za-z_!@#$*?-]+\\}?"
+    - identifier: "\\$\\{?[0-9A-Za-z_!@#$*?-]+\\}?"
 
     - constant.string:
         start: "\""