subprocess basic control job

subprocess.sh

#!/bin/bash

#Lanza subprocesos en segundo plano, manteniendo un umbral de almenos
#4 procesos en paralelo.

todo=15

echo "`date +%M:%S` Starting PARENT $$ BASHPID: $BASHPID"

while [ $todo -gt 0 ]; do
 rand=$[$RANDOM % 10]
 #simulando que terminan antes entrar a background
 #rand=0

 echo "`date +%M:%S` ALLOCATE job number $todo after $rand seconds"
 (sleep $rand; echo "`date +%M:%S` DEALLOCATE number job $todo in BASHPID: $BASHPID") &

 children=(`jobs -p`)
 echo "`date +%M:%S`   Number of children running: ${#children[@]}"
 if [ ${#children[@]} -gt 4 ]; then
   echo "`date +%M:%S`   Waiting for an available slot ..."
   wait -n ${children[@]}
 fi

 todo=$[$todo - 1]
done
echo "`date +%M:%S` waiting for the rest of children ${children[@]}"

wait
echo "`date +%M:%S` done :D"