Unofficial and WIP, for this program: https://github.com/the-weird-aquarian/Battery-Notifier (License: unlicense.org)

battery-notify4silverblue.sh

#!/usr/bin/env bash
set -e


# --- Preamble ---

# username will be pulled from arguments
program_name="battery-notify"

sourceloc_script="./$program_name.sh"
sourceloc_systemd_unit="./$program_name.service"

targetloc_prog_directory="/var/lib/battery-notify"
targetloc_script="$targetloc_prog_directory/$program_name"
targetloc_systemd_unit="/etc/systemd/system/$program_name.service"
targetloc_profiled_script="/etc/profile.d/zzz-$program_name-add-to-path.sh"
profiled_script=$(cat <<-EOF
		PATH="$targetloc_prog_directory:\$PATH"
		EOF
	)

expected_files=(
	./battery-notify.sh
	./battery-notify.service
)

# --- Functions ---

install_program() {
	for file in "${expected_files[@]}"; do
		if [ ! -f "$file" ]; then
			echo "Error: Expected file '$file' not found"
			echo "This script is meant to be run from the root of the $program_name repository"
			exit 1
		fi
	done
	install -D --mode=755 "$sourceloc_script" "$targetloc_script" && echo "OK: Installed $program_name script" || { echo "Error: Failed to install $program_name script"; exit 1; }
	install -D --mode=644 "$sourceloc_systemd_unit" "$targetloc_systemd_unit" && echo "OK: Installed $program_name systemd unit" || { echo "Error: Failed to install $program_name systemd unit"; exit 1; }

	sed -e "s|User=.*|User=$systemd_unit_username|" -e "s|ExecStart=.*|ExecStart=/bin/bash \"$targetloc_script\"|" -i "$targetloc_systemd_unit"
	cat "$targetloc_systemd_unit" | grep "User=$systemd_unit_username" &>/dev/null && echo "OK: Updated systemd unit to run as $systemd_unit_username" || { echo "Error: Failed to update systemd unit to run as $systemd_unit_username"; exit 1; }
	cat "$targetloc_systemd_unit" | grep "ExecStart=/bin/bash \"$targetloc_script\"" &>/dev/null && echo "OK: Updated systemd unit to run $targetloc_script" || { echo "Error: Failed to update systemd unit to run $targetloc_script"; exit 1; }
	
	echo "$profiled_script" >"$targetloc_profiled_script" && echo "OK: Created profile.d script" || { echo "Error: Failed to create profile.d script"; exit 1; }
	source "$targetloc_profiled_script" || { echo "Error: Failed to source '$targetloc_profiled_script'"; exit 1; }
	systemctl enable --quiet --now "$program_name.service" && echo "OK: Enabled and started $program_name systemd unit" || { echo "Error: Failed to enable and start $program_name systemd unit"; exit 1; }
	# $program_name -h || { echo "Failed to run '$program_name -h'"; exit 1; } # Messes up because we're we're running as root at this point

	echo "Done. Restart your shell or run 'source $targetloc_profiled_script' to add $program_name to your PATH variable"
	exit 0
}

uninstall_program() {
	if systemctl is-active --quiet "$program_name.service" &>/dev/null; then
		systemctl stop --quiet "$program_name.service" && echo "OK: Stopped $program_name systemd unit" || { echo "Error: Failed to stop $program_name systemd unit"; exit 1; }
	fi
	if systemctl is-enabled --quiet "$program_name.service" &>/dev/null; then
		systemctl disable --quiet "$program_name.service" && echo "OK: Disabled $program_name systemd unit" || { echo "Error: Failed to disable $program_name systemd unit"; exit 1; }
	fi
	if [ -f "$targetloc_systemd_unit" ]; then
		rm -f "$targetloc_systemd_unit" && echo "OK: Removed $program_name systemd unit" || { echo "Error: Failed to remove $program_name systemd unit"; exit 1; }
	fi
	if [ -f "$targetloc_profiled_script" ]; then
		rm -f "$targetloc_profiled_script" && echo "OK: Removed $program_name profile.d script" || { echo "Error: Failed to remove $program_name profile.d script"; exit 1; }
	fi
	if [ -f "$targetloc_script" ]; then
		rm -f "$targetloc_script" && echo "OK: Removed $program_name script" || { echo "Error: Failed to remove $program_name script"; exit 1; }
	fi
	if [ -d "$targetloc_prog_directory" ]; then
		rm -rf "$targetloc_prog_directory" && echo "OK: Removed $program_name program directory" || { echo "Error: Failed to remove $program_name program directory"; exit 1; }
	fi

	echo "Done."
	exit 0
}

elevate_privileges() {
	if [ $EUID -ne 0 ]; then
		if command -v sudo &>/dev/null; then
			exec sudo "$0" "$@"
		else
			echo "Sudo not installed, please run this script as root manually"
			exit 1
		fi
	fi
}


# --- Main ---
case "$1" in
	install)
		if [ ! "$2" ]; then
			echo "Error: No username provided"
			exit 1
		fi
		systemd_unit_username="$2"
		elevate_privileges "$@"
		install_program
		;;
	uninstall)
		elevate_privileges "$@"
		uninstall_program
		;;
	*)
		echo "Usage: $0 [install|uninstall] <username (install only)>"
		echo "The username will be used to run the systemd unit, and is expected to be a non-root user on the system"
		echo "This script will need to be run as root, but can elevate itself with sudo, if installed"
		exit 1
		;;
esac

Any chance we can fix this or use your steam OS script?