for loop over character array gives unexpected "("

Solution 1:

1. the ( unexpected error indicates you're calling your script like sh scriptname instead of bash scriptname or, preferably, chmod 755 scriptname; ./scriptname

2. Dynamic array names are hard to work with in bash. You require a temporary variable to use with indirect expansion.

   for SCANPOSITION in "${POS[@]}"
   do
       tmp="ZSPOS_${SCANPOSITION}[@]"
   
       for ZEITSCHNITT in "${!tmp}"    # note the "!"
       do
           echo "Timeslice $ZEITSCHNITT in Position $SCANPOSITION !"
       done
   done
   

3. You should always quote your "$variables" unless you know exactly why you want to leave the quotes off.

4. Also, get out of the habit of using ALL_CAPS_VARS -- some day you will accidentally use PATH and then wonder why your script is broken