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Unit 2: Red Hat Linux 9 Basics

We can find the permissions of a given file by making use of the ls program. Notes

Example: Here, we will use the command ls −l in order to display a “long” version of the
file information:
$ ls −l /usr/bin/top
−r−xr−xr−x 1 root root 56406 Sep 1215:50 /usr/bin/top

We can represent the read, write, and executable permissions by making use of the characters
r, w, and x respectively. The first part (for example, the expression −r−xr−xr−x, as shown in
the above example) signifies the file permissions. The first character signifies the file type. This
sequence comprises of three sets of three characters, that is, one set each to depict permissions of
the owner, the group, and the others.

Example: The sequence r−x signifies that only the read and execution permissions are
set. No write permission is available. Thus, this file permission specifies that every possible user
can just read and execute the file content but not modify the contents of the file.
In order to modify the permissions of files and directories, we can make use of the CLI tools such
as chmod, chown, and chgrp.

2.7.3 Concept of Managing Users

By means of the Red Hat user configuration tool, that is, “redhat−config−users”, we can
accomplish the task of adding, removing, and modifying user accounts on the system in a GUI.
This tool can be launched by selecting Main Menu  System Settings  Users and Groups. In
Figure 2.26, we have shown the primary interface of this tool.

Figure 2.26: Managing Users

It is required to provide the root password in order to use this utility. We can add, edit, or modify
users and groups by making use of this interface.
We can perform the same operations in the CLI also. The different tools used are given below:

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