Linux in a Nutshell, Fourth 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.

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