From the beginning, Linux has made it possible for admins and users to get fairly granular with file and folder permissions. From the user perspective, it’s simple: If you created a file, you own it and have permission to read or write to the file. But that doesn’t always apply to the ability to execute a file. For that, you have to add an extra permission.
It can get confusing, especially when you consider there are two ways to look at permissions: Octal and Symbolic. It is the Octal method that causes the most confusion.
This download from TechRepublic Premium will examine both of these methods of setting permissions.
From the download:
WHAT ARE PERMISSIONS?
First, we need to discuss what permissions are used for. To many admins, this is obvious. However, to those that do not know, permissions can be seen as what a user is allowed to do with a file or folder. There are typically three types of permissions you need to concern yourself with: