However, I'm a believer. For one thing, the cron maintenance scripts are clean up script intended to be run by the cron Unix utility on in order to maintain activity logs, update databases, and throw away files that need to be cleared out and/or updated from time to time. This works as it should on Unix machines that are left running 24/7, since the cron utility is programmed to run the cleanup scripts at times when the machines are theoretically at least likely to be in use. There are three scripts, designated "daily," "weekly," and "monthly. " In OS X, the daily script is scheduled to run every morning at 3:15 a.m.; the weekly script at 4:30 a.m. on Saturday mornings; and the monthly script at 5:30 a.m. on the first day of each month.
Like most Mac users, I don't leave my computer on 24/7. In fact, other than the very occasional instance of me doing in overnight software download, my computers are never on at the scheduled times, I put them to sleep or shut them off overnight, so the cron scripts never get run; and files don't get deleted; log files grow; and databases are not updated. Happily, you can manually trigger the cron scripts to run at any time you like using one of the freeware/shareware utilities mentioned above or a host of others. If you don't leave your Mac on all night, running the scirpts manually once every week or so is a good idea.
Then there's repairing permissions. While it's hard to imagine anyone arguing that running the cron scripts is useless on the majority of computers that don't stay on all the time, permissions repair is more controversial. John Gruber over at Daring Fireball calls it "voodoo."
Mac OS X incorporates a subsystem based on a UNIX-style operating system that uses permissions in the file system. Every file and folder on your hard disk has an associated set of permissions that determines who can read, write to, or execute it. For a thorough definition and discussion of OS X permissions, see this Apple Knowledge Base article:
http://docs.info.apple.com/article.html?artnum=106712
When you use Apple's Disk Utility or another maintenance utility to verify or repair disk permissions, it reviews each of the .bom files in /Library/Receipts/ and compares its list to the actual permissions on each file listed. If the permissions differ, Disk Utility reports the difference (and corrects them if you use the Repair feature).
The X-Lab notes that "there is considerable debate about performing Repair Permissions as part of regular maintenance. Our advice is that it is a good prophylactic step after installing third-party software that employs its own installer. This is primarily due to the fact that some poorly-written, third-party installers have been known to change permissions on System-related folders, then neglect to set them back, causing problems after the installation.
"Repairing permissions has gained the undeserved status of a 'magic incantation' that can fix anything, and some recommend it as part of regular maintenance. While it can be a useful troubleshooting step, we do not regard it as part of regular maintenance: it will not hurt anything, it merely wastes time when run unnecessarily. However, it is still a good idea to Repair Permissions after installing third-party software....."
Also see X-Labs' "Side effects of System cache cleaning":
http://www.thexlab.com/faqs/syscachecleaneffects.html
Personally, since it's so easy to do with OnyX, which of the dozen or or OS X system maintenance utilities out is the one I use most often, I usually just run Repair Permissions along with the cron scripts and some cache dumps using the configurable do-all Automator pane.
While this maintenance routine routine is most often an act of faith, with no really tangible evidence to indicate that it's doing anything, sometimes it does fix obvious problems.
For example, last weekend I got around to updating the second OS X system on my hard drive (I keep two systems installed on separate partitions, which allows me to, among other things, check out system updates without burning my bridges to the version I know is reliable) to OS 10.4.8. That proceeded without drama, but I was slightly pressed for time and decided to skip doing my usual OnyX maintenance run before running the OS 10.4.8 Combo updater. False economy of time.
The system installed and booted just fine, but I discovered that the Finder's "Find" function was not working (nothing would happen), and the little text search utility SpeedSearch would find document titles but not display contents summaries. Bummer. The same sort of thing once happened on my Pismo PowerBook running OS 10.4.4.
I figured I might have to run the system updater again, but decided to give OnyX a shot first. I ran the cron scripts, Repair Permissions, and some selected cache dumps, but omitted optimizing the system since the update installer had just done that. When I rebooted after OnyX had done its thing, both Find and SpeedSearch had been restored to working normally.
OnyX has a nice interface, is updated frequently, performs well, and is freeware. The latest version of OnyX is 1.7.8, which is OS 10.4.2 and up Tiger-only, but versions are still available for Mac OS X 10.3 Panther (OnyX version 1.5.3) and Mac OS X 10.1.5 Puma and 10.2 Jaguar (OnyX version 1.3.1).
Aside from OS X system maintenance and optimization, including verifying and repairing Permissions, running chron maintenance scripts, optimizing the system, verifying your disk media, and updating databases, OnyX, Like Cocktail, Mac Pilot, MainMenu, and several others, also makes it possible to configure certain hidden parameters of Finder, Dock, Safari. It allows you to customize scroll bar arrows, label lines, toggle appearance between Aqua and Graphite, show hidden system files, put a Quit Menu Item in the Finder menu, activate application and window zooming, delete certain preferences, and force empty the Trash, with or without destruction.
You can customize Dock position, alignment and minimization options, and to activate hidden and system files, transparent icons for hidden applications, animate opening applications put a menu item Quit Finder in the Dock, and relaunch the Dock. to remove a certain number of files and logs, preview the different logs and CrashReporter and more.
OnyX allows you to clean or clear selected or all Internet, user, and System caches. The browsers recognized are: Safari, Internet Explorer, Omniweb, You can enable/disable file journaling, import IE and Mozilla/Netscape bookmarks to Safari, Smooth small fonts in Safari, enable Disk Copy Expert Mode, enable Debug Menu in Safari, Address Book, and DVD Player, delete recent servers, and reset Mac OS Help.
The OnyX interface displays eight tabbed panels:
Parameters - Shows basic configuration specs; Allows you to customize scroll bar arrows, screen capture format, and many other configuration elements in the Finder, Dock, Dashboard and Exposé, Safari, The Login window ITunes, and more in seven subcategory panes
Maintenance - Lets you verify and repair Permissions, run chron scripts, optimize the system, and reset several other functions.
Cleaning - Allows you to clean or clear selected or all Internet, user, and System caches. The browsers recognized are: Safari, Internet Explorer, Omniweb, Camino (formerly Chimera), Netscape, Mozilla, Firebird (formerly Phoenix), Opera and iCab. Safari's URL icons can also be removed. Also can clean Logs, System caches, force empty the Trash, and more.
Automation - Runs Repair Permissions and all or selected maintenance routines. By default, cron scripts run automatically, but early in the AM, between 3 and 6, and only if the computer is turned on and not sleeping.
Log Files - Displays and can delete CrashReporter, Archived, and System logs selectively
Unix Utilities - The Man command allows you to format and display the Unix manual pages. You can also run the plutil, locate, and system_profiler commands from this pane.
Info - Reads out information about your computer in five sub-panes; Computer, Hardware, Disk, System, and User
Preferences - Application preferences, in which, among other things, you can banish the default "Brushed Metal" appearance theme and replace it with Aqua.

The OnyX interface is streamlined and intuitive to work with. I don't imagine anyone runs the full slate of functions. For regular tune ups, the key scripts to run are Verify And Repair Permissions, the daily, weekly, and monthly Maintain scripts, and I usually optimize the system as well, all of which can be configured in the "Automate" pane.

New in version 1.7.8:
Enable/disable the indexing of Startup Disk
You can cancel the operation before choose the Single user Startup Mode
Verification of the S.M.A.R.T. Status improved and enabled by default
Verification of the start volume at launch
Font Cache of Microsoft Office X removed
Indeterminate Progress bar while running some commands
Display of alert and error messages improved
Saving a mini, basic or full profil of your configuration
The Logic and WaveBurner Caches are not deleted anymore while deleting the applications caches
Deleting the Recent Items in the Apple menu
Help improved, corrected and updated
Korean translation
New replacement icons
Uninstaller improved
Bug corrected while modifying the saving path of screenshots
Bug corrected: The window's position is correctly saved now
Bug corrected while modifying the Safari's history parameters (-1708)
Bug while programing the scripts corrected
Random Error AppleScript -1728 after optimization and cleaning the Cache corrected
Misc little bugs corrected
System requirements:
Mac OS X 10.4.2 up
System support
PPC/Intel
OnyX is Freeware, gratis and freely usable; you may copy and distribute it at will.
For more information, visit:
http://www.titanium.free.fr/pgs/english.html
Digg this
del.icio.us
Charles W. Moore
Tags: Blogs ď OSX Odyssey ď Hot Topics ď News ď

Other Sites
Please note that launchd in Tiger will perform the system maintenance scripts when you turn on your computer if it wasn’t turned on when the scripts were scheduled to run.
So you shouldn’t need to manually run the maintenance scripts when running Mac OS X 4 or later.