set control-l-confirm

SET CONTROL-L-CONFIRM NO/yes  -  whether control-l executes a command

With the usual NO setting, when you are on a command line and use control-l,
  it clears screen and puts the current command line at the top of the 
  screen, but waits for you to press RETURN to execute the command.

If you change it to YES, in the same situation, it clears screen and
  immediately executes the command.  For example, "headers all" followed
  by control-l would clear screen and you would see the headers listed
  starting at the top of the new screen.

For more help, type "help" and one of the following:
(at any prompt:)  save-init   set   show