[*]
wait
also (optionally) takes the PID
of the process to wait for, and with $!
you get the PID
of the last command launched in the background.
Modify the loop to store the PID
of each spawned sub-process into an array, and then loop again waiting on each PID
.
# run processes and store pids in array
for i in $n_procs; do
./procs[${i}] &
pids[${i}]=$!
done
# wait for all pids
for pid in ${pids[*]}; do
wait $pid
done