While( )
Starts a while loop
While(expr)
Starts a while loop. Execution will return to this point when EndWhile( ) is called, until expr is no longer true. If a condition is met causing the loop to exit, it continues on past the EndWhile( ).
exten => 123,1,Set(COUNT=1)
exten => 123,2,While($[ ${COUNT} < 5 ])
exten => 123,3,SayNumber(${COUNT})
exten => 123,4,EndWhile( )