lol.sh

#!/usr/bin/env bash
set -euo pipefail

usage() {
  cat <<'EOF'
Usage:
  sudo ./fedora-disk-setup.sh /dev/<disk> [--swap-size 34G] [--efi-size 600M] [--boot-size 1G] [--no-mount] [--yes]

Examples:
  sudo ./fedora-disk-setup.sh /dev/nvme0n1
  sudo ./fedora-disk-setup.sh /dev/sda --swap-size 32G --yes
EOF
}

need() { command -v "$1" >/dev/null 2>&1 || { echo "Missing: $1"; exit 1; }; }

DISK="${1:-}"
[[ -z "${DISK}" || "${DISK}" == "-h" || "${DISK}" == "--help" ]] && usage && exit 0
shift || true

EFI_SIZE="600M"
BOOT_SIZE="1G"
SWAP_SIZE=""        # empty => auto (RAM + 2G)
DO_MOUNT=1
ASSUME_YES=0

while [[ $# -gt 0 ]]; do
  case "$1" in
    --efi-size)  EFI_SIZE="${2:?}"; shift 2 ;;
    --boot-size) BOOT_SIZE="${2:?}"; shift 2 ;;
    --swap-size) SWAP_SIZE="${2:?}"; shift 2 ;;
    --no-mount)  DO_MOUNT=0; shift ;;
    --yes)       ASSUME_YES=1; shift ;;
    *) echo "Unknown arg: $1"; usage; exit 1 ;;
  esac
done

[[ -b "${DISK}" ]] || { echo "Not a block device: ${DISK}"; exit 1; }

need sgdisk
need wipefs
need mkfs.fat
need mkfs.ext4
need mkswap
need mkfs.btrfs
need lsblk
need partprobe
need findmnt

# Compute swap size if not provided: RAM + 2G (rounded up to GiB)
if [[ -z "${SWAP_SIZE}" ]]; then
  mem_kib=$(awk '/MemTotal:/ {print $2}' /proc/meminfo)
  mem_gib=$(( (mem_kib + 1024*1024 - 1) / (1024*1024) ))
  swap_gib=$(( mem_gib + 2 ))
  SWAP_SIZE="${swap_gib}G"
fi

# Partition naming helper (nvme0n1p1 vs sda1)
part() {
  local n="$1"
  if [[ "${DISK}" =~ [0-9]$ ]]; then
    echo "${DISK}p${n}"
  else
    echo "${DISK}${n}"
  fi
}

echo "About to WIPE and repartition: ${DISK}"
lsblk -o NAME,SIZE,TYPE,FSTYPE,MOUNTPOINT "${DISK}" || true
echo
echo "Layout:"
echo "  1) EFI  : ${EFI_SIZE}  (FAT32)  -> /boot/efi"
echo "  2) /boot: ${BOOT_SIZE} (ext4)   -> /boot"
echo "  3) swap : ${SWAP_SIZE} (swap)   -> hibernation"
echo "  4) root : rest       (btrfs)   -> / (subvol root, home)"
echo

if [[ "${ASSUME_YES}" -ne 1 ]]; then
  read -r -p "Type YES to continue: " ans
  [[ "${ans}" == "YES" ]] || { echo "Aborted."; exit 1; }
fi

# Safety: refuse if any partitions are mounted
if findmnt -rn -S "${DISK}" >/dev/null 2>&1; then
  echo "Some part of ${DISK} is mounted. Unmount first."
  exit 1
fi

# Best-effort swapoff if this disk contains swap currently
for s in $(swapon --noheadings --raw | awk '{print $1}' | grep -E "^${DISK}" || true); do
  sudo swapoff "$s" || true
done

echo "Wiping signatures + partition table..."
wipefs -a "${DISK}"
sgdisk --zap-all "${DISK}"

echo "Creating GPT partitions..."
sgdisk -n1:1MiB:+"${EFI_SIZE}"  -t1:EF00 -c1:"EFI"  "${DISK}"
sgdisk -n2:0:+"${BOOT_SIZE}"    -t2:8300 -c2:"boot" "${DISK}"
sgdisk -n3:0:+"${SWAP_SIZE}"    -t3:8200 -c3:"swap" "${DISK}"
sgdisk -n4:0:0                  -t4:8300 -c4:"root" "${DISK}"

partprobe "${DISK}"

P1="$(part 1)"
P2="$(part 2)"
P3="$(part 3)"
P4="$(part 4)"

echo "Formatting..."
mkfs.fat -F32 -n EFI "${P1}"
mkfs.ext4 -F -L boot "${P2}"
mkswap -L swap "${P3}"
mkfs.btrfs -f -L fedora "${P4}"

if [[ "${DO_MOUNT}" -eq 1 ]]; then
  echo "Creating Btrfs subvolumes + mounting to /mnt..."
  mkdir -p /mnt
  mount "${P4}" /mnt
  btrfs subvolume create /mnt/root >/dev/null
  btrfs subvolume create /mnt/home >/dev/null
  umount /mnt

  mount -o subvol=root,compress=zstd:1 "${P4}" /mnt
  mkdir -p /mnt/{home,boot,boot/efi}
  mount -o subvol=home,compress=zstd:1 "${P4}" /mnt/home
  mount "${P2}" /mnt/boot
  mount "${P1}" /mnt/boot/efi
  swapon "${P3}"

  echo
  echo "Done. Mounted under /mnt:"
  findmnt /mnt /mnt/home /mnt/boot /mnt/boot/efi || true
  echo
  echo "Swap enabled:"
  swapon --show
else
  echo "Done. (Not mounted; --no-mount)"
fi

echo
echo "Next steps (after installing Fedora):"
echo "  - Add resume=UUID=<swap-uuid> to kernel cmdline (for hibernation resume)"
echo "  - Consider disabling zram if you want predictable hibernation behavior"