Work with Permissions

Everything you do on your Mac, and especially on the command line, is governed by permissions—which user(s) can do which things with which items, under which circumstances. In this chapter, I introduce you to file permissions, along with the closely related notions of owners and groups. I also explain how to temporarily assume the power of the root user using the sudo command.

Understand Permission Basics

As you may recall from See What’s Here, when you list files in the long format (ls -l), you can see the permissions, owner, and group of each file and directory. Every file in Mac OS X has all these attributes, and you should understand how they work because they influence what you can and can’t do with each item.

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