I am currently attempting to set up a group of 14 iMacs running 10.7.5 so that they do the following: Every weekday, turn on at 7 AM and turn off at 7 pm. (This I am able to do with the energy saver utility in system preferences). This is where it gets trickier. Ideally, I would like the iMacs to turn on at 3 AM on a saturday, and then run a simple script I've written that installs all available software updates, and then shuts down. However, neither energy saver or pmset (the unix command) allows multiple turn on and shut down points.
The partial solution I have is setting the iMacs to turn on at 7 AM every day, and have a cronjob to turn them off every weekday at 7 PM. Then, have my original cronjob that runs my script at 8 AM every Saturday, and one final cronjob that cleans up the loose end of Sunday by turning off every Sunday at 8 AM. The problem is that the iMacs are on for an hour every Sunday, which seems unclean to me. Any suggestions?