while
Execute commands
SYNTAX
      while (expr)
      ...
      end     
Execute the commands between while and the matching end while expr evaluates non-zero.
while and end must appear alone on their input lines.
break and continue may be used 
  to terminate or continue the loop prematurely. If the input is a terminal, the 
  user is prompted the first time through the loop as with foreach.
  
  "God shows his contempt for wealth by the kind of person he 
  selects to receive it" - Austin 
  O'Malley
Related commands:
  
  break - Exit from a loop
  continue - Resume the next iteration of a while or foreach loop. 
  repeat - Execute a command multiple times 
  foreach - Loop, expand words, and execute 
  commands
  
  Equivalent BASH command:
  
while - Execute commands