Updated SC3012 (markdown)

SC3012.md

@@ -18,7 +18,7 @@ First, make sure you wanted a lexicographical comparison (aka dictionary order),
 
 Then to compare as string, you can use `expr` and make sure that the strings are not interpreted numerically by adding some non-numerical data to them. Here, an apostrophe is prepended:
 
-```
+```sh
 #!/bin/sh
 x="aardvark"
 y="zebra"