dd-system.sh

#!/bin/bash
function confirm() {
	# https://stackoverflow.com/a/1885534/6732111
	read -p "Is it ok? " -n 1 -r
	echo    # (optional) move to a new line
	if [[ ! $REPLY =~ ^[Yy]$ ]]
	then
		[[ "$0" = "$BASH_SOURCE" ]] && exit 1 || return 1 # handle exits from shell or function but don't exit interactive shell
	fi
}
# sudo dd if=/dev/zero of=/dev/sdb bs=4M count=6 oflag=direct; ls /dev/sdb*
[[ $# != 2 ]] && { echo "usage: $0 /dev/sd* img.iso"; exit; };
ls -lah "$2"
stat --printf="%s\n" "$2"  # src: https://unix.stackexchange.com/a/16644/450009
lsblk -b --output SIZE -n -d "$1"
echo
echo $ sudo dd "of=$1" "if=$2"
confirm || exit
sudo dd bs=4M status=progress conv=fsync oflag=direct "of=$1" "if=$2"
sleep 2
printf "p\nn\n\n\n\n\np\n" | sudo fdisk --wipe=never -t gpt "$1"
confirm || exit
printf "p\nn\n\n\n\n\np\nw\nq\n" | sudo fdisk --wipe=never -t gpt "$1"
sync
sudo partprobe "$1"
sleep 2
ls $1*
part=$(ls $1* | tail -n1)
echo "The last partition is '$part'."
confirm || exit
sudo mkfs.ext4 "$part"
mnt="/tmp/$(uuidgen)"
mnt="${mnt,,}" # https://serverfault.com/a/103366/947767
echo "Random temporary dir: $mnt"
confirm || exit
sudo mkdir "$mnt"
sudo mount "$part" "$mnt"
echo "inxi -pildfForumxxxv8c0tmc||inxi -pildfForumxxxv 7 -c 0 -tmc" | sudo tee "$mnt/gather.sh" > /dev/null # https://gist.github.com/Nircek/acb62cdebd3b6029e160551dfc636c52
sudo chown -R 1000:1000 "$mnt"
ls -lah "$mnt"
echo Reinsert your USB stick to tease gvfs/udisks2...

That should be multiplied by 1024 or 1000 to get the capacity of drive in bytes.

https://gist.github.com/Nircek/2101dc89d0898754ca6aa67b8e799b27/db06639bed8e142e6061ca1a7f69d42acb9cf5c1#file-dd-system-sh-L15