TMP=csvtxt                                                                     # extension template
while read filename
  do    IFS="._" read -A IARR <<< $filename                                    # split filename into array containing elements and extension (${IARR[-1]})
        if [ ! "${TMP/${IARR[-1]}}" = "$TMP" -a ! "${IARR[0]}" = "HELP" ] ||   # first condition  - former $A is ${IARR[0]} now
           [ ! "${IARR[2]}" = "WE" ]                                           # second condition
          then  # update table                                                 # do whatever necessary
                echo rm $filename                                              # remove echo to remove file
        fi
  done < input