emulate [ -LR ] {zsh|sh|ksh|csh}
       Set  up  zsh options to emulate the specified shell
       as much as possible.  csh will never be fully  emu-
       lated.   If  the  argument is not one of the shells
       listed above, zsh will be used as a  default;  more
       precisely,  the tests performed on the argument are
       the same as those used to determine  the  emulation
       at startup based on the shell name, see the section
       `Compatibility' in zshmisc(1) .  If the  -R  option
       is  given,  all  options are reset to their default
       value  corresponding  to  the  specified  emulation
       mode,  except  for  certain  options describing the
       interactive  environment;  otherwise,  only   those
       options  likely  to  cause  portability problems in
       scripts and  functions  are  altered.   If  the  -L
       option  is  given,  the  options  LOCAL OPTIONS and
       LOCAL TRAPS  will  be  set  as  well,  causing  the
       effects  of  the emulate command and any setopt and
       trap commands to be local to the  immediately  sur-
       rounding  shell  function,  if  any; normally these
       options are  turned  off  in  all  emulation  modes
       except ksh.
