I've got a bit of code I'm trying to work on...
What i want to happen is ... at all times have four parallel mysql dump and imports running.

I found the follow code snippet on the forum and modified it to work
by starting four concurrent processes but it waits until all four are done before starting the next four...

 
LIST='wmi_product wmi_patches employee actions jobs appversions os hardware detection_apps status wmi_networkadapterconfig wmi_logicaldisk'
let counter=0;
for i in $LIST
do
   echo "    Dumping and Importing table $i" " ( `date +'%x %X'` ) "
   $MYSQLDUMP -h$DBHOST -u$USER -p$PASSWORD -q --opt --single-transaction --add-drop-table $DB --tables $i | $MYSQL -u$DBuser -p$DBpass $DB > $ilog.txt &
    let counter=$counter+1
    echo "$counter%4" | bc
    if [ `echo "$counter%4" | bc` -eq 0 ] ; then
          wait
    fi
done;