wait
[ID]Pause in execution until all background jobs complete (exit status 0 is returned), or pause until the specified background process ID or job ID completes (exit status of ID is returned). Note that the shell variable $! contains the process ID of the most recent background process. If job control is not in effect, ID can be only a process ID number. See the earlier section "Job Control."
wait $! Wait for most recent background process to finish