if you've got a simple command suspened, say 'mutt', and you forgot that you have already got a mutt running and try to start another mutt, the old running mutt is resumed, rather than starting a new process
bg_nice
run background jobs at lower priority
hup
send SIGHUP to background processes on exit.
notify
report status of background jobs immediately
auto_continue
if set, stopped jobs are disowned and restarted immediately
check_jobs
report status of bg-jobs if exiting a shell with job control enabled