Tcl includes two commands for looping, the while and for commands. Like the if statement, they evaluate their test the same way that the expr does.
In this lesson we discuss the while command, and in the next lesson, the for command. In most circumstances where one of these commands can be used, the other can be used as well. while test body The while command evaluates test as an expression.
If test is true, the code in body is executed. After the code in body has been executed, testis evaluated...
원문 링크 : Looping 101 - While loop
