Linux System Administration Training

The /etc/skel directory contains directories and files for users. These may be created by the installation routine when you install Linux and you can also create them yourself later. The items in skel are dependent on the Linux distribution (version) you are working on.

Linux Commands Training Tips: The Linux System Administration commands and user configuration files covered here apply to ALL other Linux distributions, including: Ubuntu, Debian, Slackware, SUSE, openSUSE, Red Hat, Fedora, Edubuntu – and Kubuntu.

Viewing the Contents of the Linux skel Directory – Example
Run the following command examples to change into the path of /etc/skel and get a long listing of the directories and files.

Depending on your Linux version and when you get it, you may see no items, or you may see some directories and files.

For example, with Red Hat, Fedora, Slackware and Debian Linux, you likely won’t see anything.
However, for SUSE and openSUSE you’ll likely see three directories named bin, Documents (containing a single hidden file) and public_html.
With Ubuntu, you’ll see a directory named Examples that contains sample data files for users to work with (which is quite a good idea).

Now add the -a option to the ls command to see all items, including hidden directories and files that begin with a period.


Superuser Root System Administrator and Superuser in Linux

Much of what a system administrator does is work that ordinary users do not have permission to do. When performing one of these tasks, the system administrator logs in as root (or uses another method; see the list starting on page 392) to have systemwide powers that are beyond those of ordinary users: A user with root privileges is referred to as Superuser. The username is root by default. Superuser has the following powers and more:

Some commands, such as those that add new users, partition hard drives, and change system configuration, can be executed only by root. Superuser can use certain tools, such as sudo, to give specific users permission to perform tasks that are normally reserved for Superuser.

Read, write, and execute file access and directory access permissions do not affect root: Superuser can read from, write to, and execute all files, as well as examine and work in all directories.
Some restrictions and safeguards that are built into some commands do not apply to root. For example, root can change any user’s password without knowing the old password.

When you are running with root (Superuser) privileges, the shell by convention displays a special prompt to remind you of your status. By default this prompt is or ends with a pound sign (#).

To lessen the chance that a user other than Superuser will try to use them by mistake, many of the utilities that Superuser runs are kept in the /sbin and /usr/sbin directories, rather than in /bin and /usr/bin. (Many of these utilities can be run by ordinary users.) You can execute these utilities by giving their full pathnames on the command line (for example, /sbin/runlevel). When you log in as root, these directories are in your PATH (page 292) by default.

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