#!/bin/sh
set -eu

mins=$1
message=${2:-Time out!}

# Calculate the sleep time in seconds
sleep_time=$(expr "$mins" \* 60)
sleep "$sleep_time"

# Send a notification using a POSIX-compliant command
# 'notify-send' is not POSIX, but we'll keep it since it's a common tool
# For complete POSIX compliance, replace this with another method if needed
notify-send -t 0 "${message}" "Your timer of $mins min is over" -u normal