This is the basics of permissions covered.
The confusion often occurs when you have to start actually setting permissions on your file server or local machine. When you use FTP or SSH or on your local terminal (if you are using Linux of course), you'll see lots of funny letters next to the files (such as rwxrw-rw-). I'll explain what all these hieroglyphics mean!
When you FTP to your web server, you'll probably see something like this next to every file and folder:
This string of letters, drwxrwxrwx, represents the permissions that are set for this folder. (Note that these are often called attributes by FTP programs.) Let's explain what each of these letters means:
d r w x r w x r w x
Owner Group Other
Directory Read Write Execute Read Write Execute Read Write Execute
As you can see, the string of letters breaks down into 3 sections of 3 letters each, representing each of the types of users (the owner, members of the group, and everyone else). There is also a "d" attribute on the left, which tells us if this is a file or a directory (folder).