Creating a Luks encrypted backup disk

set -l dev /dev/sdf
set -l part "$dev"1
set -l name epsilon

# format disk, create partition
echo -e "g\nn\n\n\n\n\nw" | sudo fdisk $dev

# create key:
head -c 128 /dev/random | base64 -w 0 | pass insert -m devices/$name

# create luks container
pass devices/$name | head -n 1 | sudo cryptsetup luksFormat $part -

# open luks container
pass devices/$name | head -n 1 | sudo cryptsetup luksOpen $part $name -

# format with exfat, label partition $name
sudo mkfs.exfat -n $name /dev/mapper/$name

# write mounts line
#  grab uuid first (do it twice, first read reads a stale value somehow)
set -l uuid (lsblk -no UUID $part | head -n 1)
set uuid (lsblk -no UUID $part | head -n 1)

while [ ! (realpath /dev/disk/by-uuid/$uuid) = $part ]
    read -l -P "Read wrong uuid, retry? [Y/n] " choice
    if [ -n "$choice" -a "$choice" != "y" -a "$choice" != "Y" ]
        return 1
    end
    set uuid (lsblk -no UUID $part | head -n 1)
end
echo "found uuid of disk $part to be $uuid."

# check if mounts file even exists
if [ -f ~/.mounts ]
    echo -e "/dev/disk/by-uuid/$uuid\t/run/media/$USER/$name\tmount-luks \$device 'devices/$name' $name\tmount-luks -u '$name'\t$name" >> ~/.mounts
    echo "wrote line to .mounts file!"
end