Conditionally perform a command zero or more times.
WHILE [NOT] condition DO command
condition Is the following :-
( expr ) Evaluate the parameter expr. A zero result is false, otherwise the condition is true. Parameter expr follows the same rules as parameter expr for command CALC. The brackets around parameter expr are mandatory and must be specified. command Specifies the command to carry out if the condition is met. Parameter command can also be another WHILE command. NOT Carry out the command only if the condition is false.
Examples on using WHILE.