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 zsh-
       misc(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 emu-
       late 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.
