Tech Tutorial: Understand and Use Essential Tools #

Introduction #

In this tutorial, we will delve into how to efficiently locate, read, and utilize system documentation within Red Hat Enterprise Linux (RHEL). Mastering these tools is crucial for any systems administrator, especially those preparing for the Red Hat Certified System Administrator (RHCSA) exam. We will focus on three primary sources of system documentation: man pages, info pages, and the /usr/share/doc directory.

Understanding how to access and interpret these resources is key to troubleshooting and mastering Linux commands and configurations. Let’s get started by exploring each tool individually.

Step-by-Step Guide #

1. The man Command #

The man command displays the manual pages for other commands and programs. It’s one of the first tools you should use when you need documentation about a command or configuration on your system.

Usage #

man [option] [command]

Example: Viewing the man page for the ls command #

man ls

This command will display the manual page for the ls command, which lists directory contents. You can navigate through the man page using the arrow keys, or search for specific terms by pressing /, typing your search term, and pressing enter.

2. The info Command #

While man pages are useful, they can sometimes be brief and lacking in practical examples. The info command provides more detailed documentation.

Usage #

info [option] [command]

Example: Viewing the info page for the grep command #

info grep

This command will show a detailed document about the grep command, complete with practical examples and in-depth descriptions. info pages are navigated similarly to web pages, using links and nodes.

3. Browsing /usr/share/doc #

This directory contains documentation and examples for many packages installed on your system. It’s a valuable resource for more in-depth information that might not be available in man or info pages.

Example: Exploring documentation for the httpd package #

ls /usr/share/doc/httpd*

This command lists all documentation available for the httpd package. You can use cat or less to read these files:

less /usr/share/doc/httpd-2.4.37/README

This will display the README file for the httpd package, which can include configuration tips, directory structures, and other useful information.

Detailed Code Examples #

Let’s consolidate our learning with a more complex, real-world example of using these documentation tools together.

Scenario: Configuring SSH #

Suppose you need to configure SSH on a RHEL system and want to ensure you understand all options available.

1. Check the man page for sshd_config:

   man sshd_config
   

   This command will show all available configuration options for the SSH daemon.

2. Use info to learn about the ssh command:

   info ssh
   

   This will provide a detailed document about the SSH client.

3. Look for additional examples or common issues in /usr/share/doc:

   ls /usr/share/doc/openssh*
   cat /usr/share/doc/openssh-server-*/README
   

   This will help you find any additional documentation or README files related to OpenSSH server.

Conclusion #

Mastering the man, info commands and understanding how to navigate and utilize the /usr/share/doc directory are fundamental skills for any RHEL system administrator. These tools provide a wealth of information that can help you understand and configure your system effectively. Regularly referring to these resources can enhance your troubleshooting skills and deepen your understanding of Linux systems. Keep exploring and practicing, and you’ll be well-prepared for the RHCSA exam and your duties as a systems administrator.