Date: 2014oct27 OS: Linux Q. How can I make my computer wake up at a specified time? A. Use the rtcwake command, like this:

rtcwake -m no -l -t `date +%s -d 'tomorrow 7:30'`

This is different than using cron. Because after you issue this command you can shutdown your computer and it will wake up at the time you want. Pretty cool. Here's a breakdown of the rtcwake options:

-m no = don't shutdown now -l = Use local time -t <time_t> = This option wants the seconds since 1970. Which you can make with the date command in backticks.