+=head3 head (list)
+
+For example:
+
+ head (["a", "b", "c"]) ⇒ "a"
+
+Returns the head (first) element of the list.
+
+=head3 join (list1, list2)
+
+For example:
+
+ join (["a", "b"], ["c", "d"]) ⇒ ["a", "b", "c", "d"]
+
+Concatenate C<list1> and C<list2>. It's not usually necessary to use
+this function since goals automatically flattens lists within lists
+into simple lists in many cases.
+
+=head3 realpath (filename)
+
+For example:
+
+ realpath ("./tests") ⇒ "/home/user/tests"
+
+Run the L<realpath(1)> command to return the resolved absolute path of
+the C<filename> parameter.
+