Handle EFI boot options as well, and an option to not reboot immediately

bin/nextboot

@@ -1,15 +1,75 @@
 #!/usr/bin/env bash
 
-PS3="Select next boot entry: "
+
+# The pretty name we want to give to the firmware entry
+biosname="Firmware Interface"
+
+while getopts ":en" opt; do
+	case $opt in 
+		e)
+			# This one is fun
+			# mapfile splits stdin on \n to an array
+			# The sed regex looks for an asterisk in the 8th position (0 indexed)
+			# It *seems* like one could put mapfile at the end of the pipeline, but
+			#  each command gets run in a subshell, so the array is lost. (ref: SC2031)
+			mapfile -t efientries < <(efibootmgr | sed -n '/.\{8\}\*/p')
+			PS3="EFI entry to BootNext: "
 			COLUMNS=1
-select entry in $(systemctl --boot-loader-entry=help) BIOS; do
-	if [[ "$entry" == "BIOS" ]]; then
-		sudo systemctl reboot --firmware-setup
-		exit 0
-	else
-		sudo systemctl reboot --boot-loader-menu=1 --boot-loader-entry="$entry"
-		exit 0
-	fi
+			select efiselection in "${efientries[@]}"; do
+				bootnext="${efiselection:4:4}"
+				break
+			done
+			sudo efibootmgr -q --bootnext "$bootnext"
+			;;
+		n)
+			noreboot=1
+			;;
+		\?)
+			echo "E: Invalid option: -$OPTARG" >&2
+			exit 1
+			;;
+	esac
 done
 
 
+# If we are trying to set the EFI entry, this conditional isn't useful
+if [[ -v bootnext ]]; then
+	:
+# If we aren't trying to set the EFI entry, and systemd-boot is installed
+elif [[ ! -v bootnext ]] && bootctl is-installed &> /dev/null; then
+	# Select prompt options
+	PS3="Select next boot entry: "
+	COLUMNS=1
+	select entry in $(systemctl --boot-loader-entry=help) "$biosname"; do
+		if [[ "$entry" == "$biosname" ]]; then
+			sudo bootctl reboot-to-firmware true
+			break
+		else
+			sudo bootctl set-oneshot "$entry"
+			break
+		fi
+	done
+else
+	# If we've made it here, then we're not trying to set the EFI entry, and 
+	#  systemd-boot is not installed in the ESP, so bail.
+	echo "E: systemd-boot not installed. Exiting."
+	exit 1
+fi
+
+# If we do want to reboot now, and we aren't setting the EFI entry
+if [[ ! -v noreboot && ! -v bootnext ]]; then 
+	# Reboot, and set a low timeout on the systemd-boot menu for next boot only
+	sudo systemctl reboot --boot-loader-menu=1 
+# If we do want to reboot now, and we are setting the EFI entry
+elif [[ ! -v noreboot && -v bootnext ]]; then
+	# Get on with it
+	sudo systemctl reboot
+# If we don't want to reboot now
+elif [[ -v noreboot ]]; then
+	echo "Next boot set."
+	exit 0
+# If things are otherwise fucked
+else
+	echo "E: You shouldn't be here..."
+	exit 1
+fi