Unix in a Nutshell, 4th Edition

Name

while

Synopsis

    while (expression)
     commands
    end

As long as expression is true (evaluates to nonzero), evaluate commands between while and end. break and continue can be used to terminate or continue the loop. See also the example under shift.

Example

set user = (alice bob carol ted)
    while ($argv[1] != $user[1])
       Cycle through each user, checking for a match
       shift user
       If we cycled through with no match...
       if ($#user == 0) then
         echo "$argv[1] is not on the list of users"
         exit 1
       endif
    end