emulate [ -LR ] {zsh|sh|ksh|csh}
       Set up zsh options to emulate the  specified  shell
       as  much  as  possible.   csh  will  never be fully
       emulated.  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
       surrounding shell function, if any; normally  these
       options  are  turned  off  in  all  emulation modes
       except ksh.
