Add make-ubuntu-usb.sh: write Ubuntu desktop ISO to USB (macOS)

Made-with: Cursor

scripts/make-ubuntu-usb.sh

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+#!/usr/bin/env bash
+# Writes Ubuntu desktop ISO to a USB stick (whole-disk, bootable).
+# Usage: make-ubuntu-usb.sh <disk_number> [iso_path]
+# Example: make-ubuntu-usb.sh 4
+#          make-ubuntu-usb.sh 4 /tmp/ubuntu-24.04.4-desktop-amd64.iso
+# Plug in the USB, run 'diskutil list' to find the disk (e.g. disk4 = use 4).
+# Use -y to skip the confirmation prompt.
+
+set -e
+SKIP_CONFIRM=
+[[ "${1:-}" == "-y" ]] && { SKIP_CONFIRM=1; shift; }
+DISK_NUM="${1:?Usage: $0 [-y] <disk_number> [iso_path]}"
+ISO="${2:-/tmp/ubuntu-24.04.4-desktop-amd64.iso}"
+
+if [[ ! -f "$ISO" ]]; then
+  echo "ISO not found: $ISO"
+  echo "Download from: https://releases.ubuntu.com/24.04/ubuntu-24.04.4-desktop-amd64.iso"
+  exit 1
+fi
+
+DISK="disk${DISK_NUM}"
+RDISK="rdisk${DISK_NUM}"
+
+if ! diskutil info "$DISK" &>/dev/null; then
+  echo "Disk $DISK not found. Run 'diskutil list' and use the number of your USB (e.g. 4 for disk4)."
+  exit 1
+fi
+
+echo "Target: $DISK ($RDISK)"
+echo "ISO:    $ISO"
+if [[ -z "$SKIP_CONFIRM" ]]; then
+  echo "This will ERASE all data on $DISK. Press Enter to continue, Ctrl+C to abort."
+  read -r
+fi
+
+diskutil unmountDisk "$DISK"
+# macOS dd uses bs in bytes; 4m is invalid, use 4MiB. status=progress is GNU-only.
+sudo dd if="$ISO" of="/dev/$RDISK" bs=4194304
+diskutil eject "$DISK"
+echo "Done. USB is now a bootable Ubuntu installer."