Control statements, such as if, while, and so on,
control the flow of execution in awk programs. Most of awk’s
control statements are patterned after similar statements in C.
All the control statements start with special keywords, such as if
and while, to distinguish them from simple expressions.
Many control statements contain other statements. For example, the
if statement contains another statement that may or may not be
executed. The contained statement is called the body.
To include more than one statement in the body, group them into a
single compound statement with braces, separating them with
newlines or semicolons.