Mac OS X maintenance scripts
Mac OS X, out of the box, performs several chores overnight -- some every night, others on a weekly basis, and still more on a monthly basis -- as part of its periodic maintenance scripts. They clean up unnecessary junk files, rotate log files, and generally do the sort of things you would expect to be done on a regular basis to make sure that your civilized computer is kept in good working order.
These maintenance scripts are run by the "periodic" utility, which is called from a "cron job" (a timed event that happens on a schedule or a repeating basis) that is triggered at specific times. All of the out-of-the-box maintenace scripts are run overnight; that's when the "cron" utility triggers them.
It is for this reason that we generally recommend letting your computer run overnight on both weekdays and weekends. The daily, weekly, and monthly maintenance scripts do their magic overnight -- and this can be vital to the operation and security of your computer. If the computer is not on overnight, it can't run any of the maintenance tasks. The computer does go into successive power-saving modes, so it consumes far less energy overnight than it would during the day, while you're actively using it. If you have concerns about the tradeoff between energy savings and automatic system maintenance, please contact us and we can work out a solution that fits your needs.
Under certain circumstances, we have found that maintenance scripts run even when your computer is set to go to sleep overnight -- which is, of course, a good idea to enable, because it saves power. This may be true on newer computers, purchased since the introduction of the Power Macintosh G4 in summer 1999. Some models exhibit deeper sleep behavior for maximum power savings, and this may shut down their ability to run the overnight maintenance.
The "periodic" command itself just runs all of the commands inside a specified folder, under /etc/periodic. So "periodic weekly" runs all commands in /etc/periodic/weekly. This can be handy; you can create your own folders there and hook them to events. (We intend to deploy RIT systems with more standard folders wired up to more times and event triggers that the operating system provides.)
If the periodic maintenance scripts have not run recently, they should be run. This can fix problems with your computer and may contribute to a performance improvement. You may run them manually by typing "sudo periodic daily" or "sudo periodic weekly" or "sudo periodic monthly" at the command line. To run these commands, you will need an administrator-level account.
