#! /bin/bash

shopt -s extglob

packet_size=1280
packets_per_dataset=50

rm -f roof_test.raw
for packet in $(seq 0 24); do
    for id in $(seq 1 16); do
        name=$(ls -- *$id.@(fx|dat) | grep -P "_0?$id\.\w+")
        echo "Appending packet $packet from $name "
        dd if=$name of="roof_test.raw" bs=$packet_size count=$packets_per_dataset skip=$((packet * $packets_per_dataset))  oflag=append conv=notrunc status=none
    done
done