Permission Facts Every file has an inode (information node) that stores information about the file, including when the file was last modified, file size, data block location, permissions, and ownership (remember, directories are also files in the Linux system). The portion of the inode that stores permission information is called the mode. The mode has

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User Account Security The root User Account The root user account is the Linux system superuser. It is created during the installation process, and it receives the account number 0 (zero). (Normal user accounts receive ascending numbers beginning at 500.) As such, the root user can perform any task. Because of this, it is important

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User and Group Facts User accounts control the ability to log on to a system, access resources, and perform certain actions. Groups provide a means of grouping users for administrative purposes such as assigning permissions to files. When you work with users and groups, you will use a friendly name (such as mary or sales)

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Environment Variable Facts An environment variable is a setting that the operating system or programs working in the operating system access. Environment variables make up the user environment. The standard for writing variables names (called variable identifiers) is to use upper case. When you create a variable (called a user-defined variable), it applies only to

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