How to do defragment disk on Mac?

Use the procedure testing and repairing a disk or volume. This information is located under disc/utility located in the applications/utilities. Follow the four steps described. By the way always use the help menu to located information about the MAC it will save you a lot of time.

I believe the Mac OSX is similar to most Linux file systems. It does not need to be defragmented in the same manner that Windows systems need. File maintenance is not required in the same manner and whatever is needed generally takes place in the background.

Norton Utilities and Techtool Pro are third party applications for Macs. Cocktail (10 day free trial) can be used for cleaning caches, optimizing ect. Or just launch Disc Utilities choose the disc you want to check and follow directions.

As the above but also remember to both leave your Mac on over night and/or turn it off occasionally. The computer does some maintenance scheduled at night, and at start-up (see Mlsstl and the reason for restart advice from the Sfar link).

There is another Mac utility called MacJanitor, it cleans up the disc without having to leave your computer on all night.

You can download it here for free.

One more suggestion, especially if you run any Microsoft applications on your mac or do file sharing.

Download Peer Guardian and it will block attempts at spying from government, Edu, Internet providers, Spyware, Microsoft Corp and others.

It too is free. I've had file sharing sessions where as many as 2 thousand hits were made on my computer, all turned away by this free application.

http://phoenixlabs.org/pgosx/