The helpfulness of verifying and repairing file permissions in OS X is debatable , and in OS X El Capitan, Apple’s removed the option from Disk Utility altogether, favoring repairing permissions automatically. Some crazy circumstance might come up where you have to do it manually though, which is why OS X Daily points out the command line method is useful. Read more… 
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Verify and Repair Permissions from the Command Line in OS X El Capitan
			
			
 If you’re getting ready to set up a new computer or you need to format an old one, it’s useful to get a quick glimpse at everything you have installed so you can easily reinstall them later. OS X Daily shows how to do it with a Terminal command. Read more…