cd Options
autocd
if a directoryname is entered like a command, and there is no command of that name; the 'cd' command is executed for that directory
auto_pushd
make cd push the old directory to the dirstack
cdable_vars
if cd would fail, because the arg is not a dir, try to expand the argument as if it was called the ~expression way
pushd_ignore_dups
don't push dups on the dirstack
pushd_to_home
make 'pushd' with no argument, act like
pushd ${HOME}