if

if ( condition )
    statement
[else
    statement ]

If condition is true, do statement(s) ; otherwise do statement in the optional else clause. The condition can be an expression using any of the relational operators < , <= , == , != , >= , or > , as well as the array membership operator in , and the pattern-matching operators ~ and !~ (e.g., if ($1 ~ /[Aa].*/) ). A series of statements must be put within braces. Another if can directly follow an else in order to produce a chain of tests or decisions.