Understand and Use Essential Tools

Introduction

In this challenge, you will explore essential Linux tools and file management techniques. You'll work with file permissions, create hard and soft links, use the find command, manipulate log files, and work with compressed archives. These skills are fundamental for any Linux system administrator and are frequently tested in RHCSA exams.

Environment

LabEx uses Red Hat Universal Base Image 9 (UBI9) to simulate the exam environment. It may not be identical to the actual RHCSA exam environment, but it provides a good representation of the tasks you'll encounter.

There are two users in the environment:

• labex: A standard user with sudo privileges, password: labex.
• root: The system administrator, password: redhat.

The challenge features real exam questions, along with explanations, requirements, and automated verification scripts to help you confirm task completion. It effectively simulates the knowledge areas covered in the RHCSA exam.

Skills Graph

File Search and Log Management

In this step, you'll use the find command to locate specific files and manipulate log files.

Tasks

• Find all setuid files on the system and save the list to a file.
• Search for specific log messages and create an archive of log files.

Requirements

• Create a file named setuid_list in the /home/labex directory containing a list of all setuid files on the system.
• Create a file named logs in the /home/labex directory containing all log messages from /var/log/messages that include the term "ACPI".
• Create a compressed tar archive of the entire /var/log directory and save it as log_archive.tgz in the /home/labex directory.

Example

After completing this step, you should have the following files in your /home/labex directory:

setuid_list
logs
log_archive.tgz

The setuid_list file might contain entries like:

/usr/bin/sudo
/usr/bin/newgrp
/usr/bin/chage
...

Working with Compressed Archives

In this step, you'll create and extract compressed tar archives using different compression methods.

Tasks

• Create compressed tar archives of the /home directory using gzip and bzip2 compression.
• Extract the contents of these archives.

Requirements

• Create a gzip-compressed tar archive of the /home directory named home.tar.gz in the /home/labex directory.
• Create a bzip2-compressed tar archive of the /home directory named home.tar.bz2 in the /home/labex directory.
• Extract both archives into separate directories named gzip_extract and bzip2_extract in the /home/labex directory.

Example

After completing this step, you should have the following files and directories in your /home/labex directory:

home.tar.gz
home.tar.bz2
gzip_extract/
bzip2_extract/

Managing Hard and Soft Links

In this step, you'll create and manage hard and soft links, observing how they behave when files are modified or deleted.

Tasks

• Create hard links and observe their behavior.
• Create a soft link and observe its behavior when the target file is modified or deleted.

Requirements

• Create two hard links to original named hard1 and hard2 in the same directory.
• Create a soft link named soft1 in the /home/labex directory, pointing to original.
• Modify the content of hard2 and observe the changes in other files.
• Delete original and observe the behavior of the links.

Example

After creating the links, you should see something like this when listing the files:

$ ls -li /home/labex/original /home/labex/hard1 /home/labex/hard2 /home/labex/soft1
ls: cannot access '/home/labex/original': No such file or directory
1234567 -rw-rw-r-- 3 labex labex 0 Aug 27 10:00 /home/labex/hard1
1234567 -rw-rw-r-- 3 labex labex 0 Aug 27 10:00 /home/labex/hard2
1234568 lrwxrwxrwx 1 labex labex 8 Aug 27 10:01 /home/labex/soft1 -> original

Note that the hard links share the same inode number, while the soft link has a different inode.

Managing File Permissions

In this step, you'll practice managing file permissions using both symbolic and numeric notation.

Tasks

• Create a file and modify its permissions using both symbolic and numeric notation.
• Observe how different permission combinations affect file access.

Requirements

• Create a file named perm_file in the /home/labex directory.
• Set initial permissions to read-only for owner, group, and others.
• Modify permissions to add execute for owner, write for group, and write for others.
• Set permissions to read, write, and execute for all users in a single command.
• Remove write permission for group and others.

Example

After completing the permission changes, the file permissions should look like this:

$ ls -l /home/labex/perm_file
-rwxr-xr-x 1 labex labex 0 Aug 27 09:38 /home/labex/perm_file

Summary

In this challenge, you practiced essential Linux file management skills. You learned how to use the find command to locate specific files, manipulate log files, create and extract compressed archives, work with hard and soft links, and manage file permissions. These skills are fundamental for system administration and are often tested in RHCSA exams.