WHILE

WHILE condition
   ...
END

or

DO WHILE condition
   ...
END

Provided that the conditional expressioncondition holds true, the commands in the block enclosed by the WHILE, or DO WHILE, and the corresponding END statement are repeatedly executed until condition becomes false.

To put it more bluntly: The condition is always tested on the begin of the loop, that is, before executing the respective block of commands. With S_TOOLE-STx, there is no explicit loop statement checking its condition at the end of the loop, but if this is what you are longing for, you will find relief by combining the FOREVER statement with an appropriate Programmer_Guide/Command_Reference/IF|IF]], and BREAK, statement.