Adminbook Exercise Answers on Markelov.Dev

Chapter 10: Networking Answers

Mon, 01 Jan 0001 00:00:00 +0000

Topics

Network interface configuration
NetworkManager (nmcli)
Static and DHCP configurations
Hostname and DNS management
Firewall configuration (firewall-cmd)

exercise_01.sh

executable safe: yes

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 1: Use the ip a command to list all network interfaces. 
# Identify the IP address, netmask (in CIDR format), and MAC address for your primary Ethernet interface.
#
# Task: Display network interface information.

ip addr show

exercise_02.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 2: Use the ip route show command to display the system's current routing table. 
# Identify the default gateway and its associated metric.
#
# Task: Display routing table with gateway information.

ip route show

exercise_03.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 3: Use nmcli con show to list all available NetworkManager connection profiles. 
# Identify which connections are currently active and on which devices.
#
# Task: List all NetworkManager connections and their status.

nmcli connection show

exercise_04.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 4: Use nmcli to display all properties for your primary active connection. 
# Note the ipv4.method value.
#
# Task: Display detailed connection properties.

# Get the active connection name
ACTIVE_CON=$(nmcli -t -f NAME,DEVICE connection show --active | head -n1 | cut -d: -f1)

echo "Displaying properties for: $ACTIVE_CON"
echo ""

nmcli con show "$ACTIVE_CON"

exercise_05.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 5: Add a new, persistent NetworkManager connection named lab-dhcp 
# for your second (likely disconnected) Ethernet interface. 
# Ensure it is configured to get an IP address automatically via DHCP and to autoconnect.
#
# Task: Create a new DHCP-based network connection.
#
# Note: Replace 'enp8s0' with your actual second network interface name.

# You may need to identify your second interface first with: ip link show

sudo nmcli con add con-name lab-dhcp type ethernet ifname enp8s0 \
  ipv4.method auto \
  connection.autoconnect yes

echo ""
echo "Connection 'lab-dhcp' created."
nmcli connection show

exercise_06.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 6: Create a new, persistent connection named static1 for your primary interface. 
# Configure it with the following manual settings:
# IP Address: 192.168.122.55/24
# Gateway: 192.168.122.1
# DNS Server: 8.8.8.8
# Autoconnect: no
#
# Task: Create a static IP network configuration.
#
# Note: Replace 'enp1s0' with your actual primary interface name.

sudo nmcli con add con-name static1 type ethernet ifname enp1s0 \
  ipv4.method manual \
  ipv4.addresses 192.168.122.55/24 \
  ipv4.gateway 192.168.122.1 \
  ipv4.dns 8.8.8.8 \
  connection.autoconnect no

echo ""
echo "Connection 'static1' created successfully."
nmcli connection show

exercise_07.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 7: Bring the static1 connection up. 
# Use ip a and ip route to verify that the static IP and new default gateway are active.
#
# Task: Activate a network connection and verify its status.

sudo nmcli con up static1

echo ""
echo "=== IP Address Information ==="
ip a

echo ""
echo "=== Routing Table ==="
ip route

exercise_08.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 8: Add a second IP address, 10.10.10.55/24, to your active static1 connection. 
# Do not remove the original 192.168.122.55/24 address. 
# Verify with ip a that the interface now has both IP addresses.
#
# Task: Add a secondary IP address to an existing connection.

sudo nmcli con mod static1 +ipv4.addresses 10.10.10.55/24

sudo nmcli con up static1

echo ""
echo "Verifying both IP addresses:"
ip a show enp1s0

exercise_09.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 9: Change your system's persistent hostname to server15.test.local.
#
# Task: Set a new system hostname.

sudo hostnamectl set-hostname server15.test.local

echo "Hostname changed to server15.test.local"
echo "Please re-open your shell session to see the change."
echo ""
echo "Current hostname:"
hostnamectl

exercise_10.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 10: Edit the /etc/hosts file to add a new entry. 
# The entry should map the IP address 192.168.122.55 to the hostnames web55.test.local and web55.
#
# Task: Add a hosts file entry.

echo "192.168.122.55  web55.test.local web55" | sudo tee -a /etc/hosts

echo ""
echo "Entry added to /etc/hosts:"
grep "web55" /etc/hosts

exercise_11.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 11: Modify your active connection profile to use the static DNS servers 8.8.8.8 and 8.8.4.4
#
# Task: Configure custom DNS servers for a network connection.

# Get the active connection name
ACTIVE_CON=$(nmcli -t -f NAME,DEVICE connection show --active | grep -v '^lo:' | head -n1 | cut -d: -f1)

echo "Modifying connection: $ACTIVE_CON"

sudo nmcli con mod "$ACTIVE_CON" ipv4.dns "8.8.8.8 8.8.4.4"

sudo nmcli con up "$ACTIVE_CON"

echo ""
echo "DNS servers configured. Contents of /etc/resolv.conf:"
cat /etc/resolv.conf

exercise_12.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 12: Modify the same connection profile to set ipv4.ignore-auto-dns to yes. 
# Reactivate the connection and then inspect the /etc/resolv.conf file 
# to ensure only your manually set DNS servers are present.
#
# Task: Ignore DHCP-provided DNS servers and use only manually configured ones.

# Get the active connection name
ACTIVE_CON=$(nmcli -t -f NAME,DEVICE connection show --active | grep -v '^lo:' | head -n1 | cut -d: -f1)

echo "Modifying connection: $ACTIVE_CON"

sudo nmcli con mod "$ACTIVE_CON" ipv4.ignore-auto-dns yes

sudo nmcli con up "$ACTIVE_CON"

echo ""
echo "Auto-DNS ignored. Contents of /etc/resolv.conf:"
cat /etc/resolv.conf

exercise_13.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 13: Add the http service to the default zone's runtime configuration. 
# Verify it is listed. Then, reload the firewall using firewall-cmd --reload 
# and verify that the http service is now gone (because it was not permanent).
#
# Task: Demonstrate temporary vs permanent firewall rules.

echo "Adding http service temporarily..."
sudo firewall-cmd --add-service=http

echo ""
echo "Current services (runtime):"
sudo firewall-cmd --list-services

echo ""
echo "Reloading firewall..."
sudo firewall-cmd --reload

echo ""
echo "Services after reload (http should be gone):"
sudo firewall-cmd --list-services

exercise_14.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 14: Permanently add TCP port 8080 to the public zone. 
# Reload the firewall and verify that the port is now active in the runtime configuration.
#
# Task: Add a permanent firewall rule for a custom port.

sudo firewall-cmd --zone=public --add-port=8080/tcp --permanent

echo "Port 8080/tcp added permanently."
echo ""

echo "Reloading firewall..."
sudo firewall-cmd --reload

echo ""
echo "Open ports in public zone:"
sudo firewall-cmd --zone=public --list-ports

Chapter 11: SELinux Answers

Mon, 01 Jan 0001 00:00:00 +0000

Topics

SELinux contexts
File and port labeling
SELinux booleans

exercise_01.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 1: Write the two commands necessary to check the SELinux context (label) 
# for both the running sshd process and the /etc/ssh/sshd_config file.
#
# Task: Display SELinux contexts for process and file.

echo "=== SELinux context for sshd process ==="
ps -eZ | grep sshd

echo ""
echo "=== SELinux context for /etc/ssh/sshd_config ==="
ls -Z /etc/ssh/sshd_config

exercise_02.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 2: You have created a new directory, /srv/www/, which needs to be served by Apache. 
# Write the two commands required to permanently set the context for this directory 
# and all its contents to httpd_sys_content_t.
#
# Task: Set SELinux context for Apache web content directory.

# Add the context rule permanently
sudo semanage fcontext -a -t httpd_sys_content_t "/srv/www(/.*)?"

# Apply the context to the directory
sudo restorecon -Rv /srv/www

echo ""
echo "SELinux context has been set for /srv/www"

exercise_03.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 3: The company wants to run a secondary HTTP server on port 8988. 
# Write the command to permanently label TCP port 8988 as a valid http_port_t port.
#
# Task: Add a custom port to SELinux http_port_t type.

sudo semanage port -a -t http_port_t -p tcp 8988

echo ""
echo "Port 8988 has been added to http_port_t"
echo ""

sudo semanage port -l | grep http_port_t

exercise_04.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 4: Find and enable the SELinux boolean permanently that allows the Apache web server to use NFS.
#
# Task: Enable SELinux boolean for Apache NFS access.

echo "Searching for NFS-related Apache booleans..."
sudo semanage boolean -l | grep nfs | grep http

echo ""
echo "Enabling httpd_use_nfs boolean permanently..."
sudo setsebool -P httpd_use_nfs on

echo ""
echo "Boolean has been enabled."

Chapter 2: Documentation and Basic Commands Answers

Mon, 01 Jan 0001 00:00:00 +0000

Topics

Man pages, info pages
Bash aliases
Find command and pipes
Vim tutorial

exercise_01.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 1: Check the man page for the file passwd to find the name of the fifth field and why it has this name.
#
# Task: Use the man command to view the passwd file format documentation
# and identify what the fifth field represents.

man 5 passwd

exercise_02.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 2: Call info info and read tutorial. If missed install info package.
#
# Task: Open the info documentation system's tutorial to learn how to use info pages.

info info

exercise_03.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 3: Find in the bash manual page description of aliases and create an alias lls for ls -lah
#
# Task: Search the bash man page for ALIASES section and create a persistent alias
# for the 'ls -lah' command named 'lls'.

# First, view the bash manual for aliases
# man bash
# Type /ALIASES and press Enter to search

# Create the alias in .bashrc
echo "alias lls='ls -lah'" >> ~/.bashrc

# Apply the changes to the current session
source ~/.bashrc

echo "Alias 'lls' has been created for 'ls -lah'"

exercise_04.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 4: By using a pipe and a find tool, make a command that will display the number 
# of files in the /etc directory containing "an" in the name.
#
# Task: Use find to search for files with "an" in their names in /etc directory,
# and count them using wc.

find /etc -type f -name "*an*" 2>/dev/null | wc -l

exercise_05.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 5: Run the command vimtutor and follow the exercises (it will take about 20 minutes).
#
# Task: Launch the interactive Vim tutorial to learn basic Vim text editor commands.

vimtutor

exercise_extra_01.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Extra Exercise 1: Use the find command to locate all files in /var/log that were 
# modified in the last 24 hours. Sort the results by modification time (newest first).
#
# Task: Find recently modified log files using find with -mtime.

echo "Files in /var/log modified in the last 24 hours (newest first):"
echo ""
find /var/log -type f -mtime -1 2>/dev/null | xargs ls -lt 2>/dev/null | head -20

exercise_extra_02.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Extra Exercise 2: Create a command pipeline that reads /etc/passwd, extracts 
# all unique shells (field 7), sorts them, and displays how many users use each shell.
#
# Task: Use cut, sort, uniq in a pipeline to analyze shell usage.

echo "Shell usage statistics from /etc/passwd:"
echo ""
cut -d: -f7 /etc/passwd | sort | uniq -c | sort -rn

exercise_extra_03.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Extra Exercise 3: Use the head and tail commands together to extract lines 10-20
# from /etc/passwd. Then use sed to achieve the same result.
#
# Task: Extract a range of lines from a file using different methods.

echo "=== Using head and tail ==="
head -20 /etc/passwd | tail -11

echo ""
echo "=== Using sed ==="
sed -n '10,20p' /etc/passwd

echo ""
echo "=== Using awk ==="
awk 'NR>=10 && NR<=20' /etc/passwd

Chapter 3: Bash Scripting Answers

Mon, 01 Jan 0001 00:00:00 +0000

Topics

Argument processing
File and directory operations
Conditional statements and loops
Test operators

exercise_01.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 1: Create a script that takes two numbers as command-line arguments and prints their sum.
#
# Task: Accept two numeric arguments, validate them, and calculate their sum.

if [ $# -ne 2 ]; then
    echo "Error: Two numbers required"
    echo "Usage: $0 number1 number2"
    exit 1
fi

if ! [[ "$1" =~ ^-?[0-9]+$ ]] || ! [[ "$2" =~ ^-?[0-9]+$ ]]; then
    echo "Error: Both arguments must be numbers"
    exit 1
fi

sum=$(( $1 + $2 ))
echo "Sum of $1 and $2 is: $sum"

exercise_02.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 2: Write a script that checks if a file provided as a command-line argument exists.
#
# Task: Accept a filename as an argument and check if it exists as a regular file,
# directory, or doesn't exist at all.

if [ $# -eq 0 ]; then
    echo "Error: No filename provided"
    echo "Usage: $0 filename"
    exit 1
fi

filename="$1"

if [ -f "$filename" ]; then
    echo "File '$filename' exists"
    ls -lh "$filename"
    exit 0
elif [ -d "$filename" ]; then
    echo "'$filename' is a directory, not a regular file"
    exit 2
else
    echo "File '$filename' does not exist"
    exit 1
fi

exercise_03.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 3: Create a script that creates a directory if it doesn't already exist.
#
# Task: Accept a directory name as an argument and create it if it doesn't exist.
# Handle cases where a file with the same name exists.

if [ $# -eq 0 ]; then
    echo "Error: No directory name provided"
    echo "Usage: $0 directory_name"
    exit 1
fi

dirname="$1"

if [ -d "$dirname" ]; then
    echo "Directory '$dirname' already exists"
    ls -ld "$dirname"
    exit 0
fi

if [ -e "$dirname" ]; then
    echo "Error: '$dirname' exists but is not a directory"
    exit 1
fi

if mkdir -p "$dirname"; then
    echo "Directory '$dirname' created successfully"
    ls -ld "$dirname"
    exit 0
else
    echo "Failed to create directory '$dirname'"
    exit 1
fi

exercise_04.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 4: Create a script that performs a numeric countdown from a given starting number to 1.
# If no argument is provided or the argument is not a positive integer, print an error message and exit.
#
# Task: Count down from a specified positive integer to 1, with input validation.

if [ $# -eq 0 ]; then
    echo "Error: No starting number provided"
    echo "Usage: $0 positive_integer"
    exit 1
fi

start="$1"

if ! [[ "$start" =~ ^[0-9]+$ ]]; then
    echo "Error: '$start' is not a valid positive integer"
    exit 1
fi

if [ "$start" -le 0 ]; then
    echo "Error: Number must be greater than 0"
    exit 1
fi

echo "Starting countdown from $start..."
for ((i=start; i>=1; i--)); do
    echo "$i"
done

echo "Countdown complete!"

exercise_05.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 5: Write a script that lists all executable regular files in the current directory.
#
# Task: Find all files in the current directory that are both regular files and executable,
# then display them with file details.

echo "Executable files in current directory:"

count=0

for file in *; do
    if [ -f "$file" ] && [ -x "$file" ]; then
        ls -lh "$file"
        ((count++))
    fi
done

echo "Total executable files found: $count"

if [ $count -eq 0 ]; then
    echo "No executable files found"
    exit 1
else
    exit 0
fi

exercise_extra_01.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Extra Exercise 1: Write a script that takes a filename as an argument
# and displays the number of lines, words, and characters in the file.
# If no argument is provided, print a usage message.

if [ $# -eq 0 ]; then
    echo "Usage: $0 <filename>"
    exit 1
fi

FILE="$1"

if [ ! -f "$FILE" ]; then
    echo "Error: File '$FILE' does not exist or is not a regular file."
    exit 1
fi

LINES=$(wc -l < "$FILE")
WORDS=$(wc -w < "$FILE")
CHARS=$(wc -c < "$FILE")

echo "File: $FILE"
echo "Lines: $LINES"
echo "Words: $WORDS"
echo "Characters: $CHARS"

exercise_extra_02.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Extra Exercise 2: Write a script that generates a simple multiplication table
# for a number provided as an argument. Display the table from 1 to 10.
# Use a for loop with the seq command.

if [ $# -eq 0 ]; then
    echo "Usage: $0 <number>"
    exit 1
fi

NUM="$1"

# Validate that the argument is a number
if ! [[ "$NUM" =~ ^-?[0-9]+$ ]]; then
    echo "Error: '$NUM' is not a valid integer."
    exit 1
fi

echo "Multiplication table for $NUM:"
echo "=============================="

for i in $(seq 1 10); do
    RESULT=$((NUM * i))
    printf "%d x %2d = %d\n" "$NUM" "$i" "$RESULT"
done

exercise_extra_03.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Extra Exercise 3: Write a script that monitors a given log file and
# counts the number of ERROR, WARNING, and INFO lines.
# Accept the log file path as an argument. Use grep -c for counting.

if [ $# -eq 0 ]; then
    echo "Usage: $0 <logfile>"
    exit 1
fi

LOGFILE="$1"

if [ ! -f "$LOGFILE" ]; then
    echo "Error: File '$LOGFILE' does not exist."
    exit 1
fi

ERRORS=$(grep -ci "error" "$LOGFILE")
WARNINGS=$(grep -ci "warning" "$LOGFILE")
INFOS=$(grep -ci "info" "$LOGFILE")
TOTAL=$(wc -l < "$LOGFILE")

echo "Log file analysis: $LOGFILE"
echo "=============================="
echo "Total lines:  $TOTAL"
echo "ERROR lines:  $ERRORS"
echo "WARNING lines: $WARNINGS"
echo "INFO lines:   $INFOS"

if [ "$ERRORS" -gt 0 ]; then
    echo ""
    echo "Last 5 ERROR lines:"
    grep -i "error" "$LOGFILE" | tail -5
fi

Chapter 4: User and Group Management Answers

Mon, 01 Jan 0001 00:00:00 +0000

Topics

Creating users and groups
User modification and deletion
Password aging policies
Sudo configuration

exercise_01.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 1: Create a new devusers group. Create new users named devuser1, devuser2, and devuser3,
# and add them to the devusers group. Add devuser1 to the wheel group.
#
# Task: Set up a new group and three users with proper group memberships.

sudo groupadd devusers
sudo useradd -G devusers devuser1
sudo useradd -G devusers devuser2
sudo useradd -G devusers devuser3
sudo usermod -aG wheel devuser1

# Set passwords for the users
echo "Password for user devuser1"
sudo passwd devuser1
echo "Password for user devuser2"
sudo passwd devuser2
echo "Password for user devuser3"
sudo passwd devuser3

# Verify user configurations
id devuser1
id devuser2
id devuser3

# Verify group memberships
getent group wheel
getent group devusers

exercise_02.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 2: Modify the devuser3 account. Change the comment field to "Senior Developer - devuser3",
# add him to an existing secondary group named sshd, and change their default shell to /usr/sbin/nologin.
# Ensure that existing secondary groups are preserved.
#
# Task: Modify user attributes including comment, shell, and group membership.

sudo usermod -c "Senior Developer - devuser3" -aG sshd -s /usr/sbin/nologin devuser3

# Verify the changes
getent passwd devuser3
id devuser3

exercise_03.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 3: Lock the devuser2 account. Verify the change by checking entry in /etc/shadow.
#
# Task: Lock a user account and verify the lock status in the shadow file.

sudo usermod -L devuser2

# Verify the lock (should see '!' before the password hash)
sudo grep devuser2 /etc/shadow

exercise_04.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 4: Delete the devuser2 account, ensuring the home directory is also deleted.
# Verify that the entry is no longer in /etc/passwd.
#
# Task: Remove a user account completely including their home directory.

sudo userdel -r devuser2

# Verify deletion
sudo grep devuser2 /etc/shadow
sudo ls /home

exercise_05.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 5: For devuser1, set the minimum number of days between password changes to 8 and 
# the maximum number of days to 40. Set the warning period before devuser1's password expires 
# to 14 days. Force devuser1 to change their password on the next login. 
# Set the devuser1's account to expire on December 30, 2028.
#
# Task: Configure password aging and account expiration settings for a user.

sudo chage -m 8 -M 40 -W 14 -d 0 -E 2028-12-31 devuser1

# Verify the settings
sudo chage -l devuser1

exercise_06.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 6: Create a new file /etc/sudoers.d/devs using visudo with option -f. 
# In this new file, add a rule that allows the user devuser2 to run all commands as root 
# without needing a password. Add a rule that allows the group devusers to run all commands 
# defined by alias SERVICES from /etc/sudoers as root that require a password. 
# Make sure SERVICES is uncommented in /etc/sudoers.
# Will devuser2 be required to use a password for /usr/bin/systemctl start?
#
# Task: Configure sudo rules for users and groups with specific permissions.

# Create the sudoers file using visudo
sudo visudo -f /etc/sudoers.d/devs

# Add these lines to the file:
# devuser2 ALL=(ALL) NOPASSWD: ALL
# %devusers ALL=(ALL) SERVICES

# Answer: No, devuser2 will not be required to use a password for /usr/bin/systemctl start
# because devuser2 has NOPASSWD for ALL commands.

echo "After running this script, edit /etc/sudoers.d/devs with:"
echo "devuser2 ALL=(ALL) NOPASSWD: ALL"
echo "%devusers ALL=(ALL) SERVICES"

Chapter 5: Disk Management and LVM Answers

Mon, 01 Jan 0001 00:00:00 +0000

Topics

Disk partitioning (fdisk)
Physical volumes and volume groups
Logical volumes
LVM cleanup

exercise_01.sh

instructional safe: yes requires: /dev/sdb

Download .sh View on GitHub

#!/bin/bash
# @type: instructional
# @requires: /dev/sdb
# @safe: yes

# Exercise 1: Assuming you have a new, unpartitioned 20Gb disk named /dev/sdb. 
# Use fdisk /dev/sdb to enter the interactive mode. Create a new DOS (MBR) partition table for the disk. 
# Create one primary partition of 2 Gb and one extended partition. 
# Within the extended partition, create two logical partitions of 500 MiB each.
#
# Task: Create MBR partition table with primary and logical partitions using fdisk.
#
# WARNING: This script requires a disk device and will modify it. Use with caution!

echo "This script demonstrates the fdisk commands needed."
echo "Run: sudo fdisk /dev/sdb"
echo ""
echo "Commands to enter in fdisk:"
echo "n          - Create new partition"
echo "p          - Primary partition"
echo "1          - Partition number 1"
echo "[Enter]    - First sector (default)"
echo "+2G        - Size of 2GB"
echo ""
echo "n          - Create new partition"
echo "e          - Extended partition"
echo "2          - Partition number 2"
echo "[Enter]    - First sector (default)"
echo "[Enter]    - Last sector (use remaining space)"
echo ""
echo "n          - Create logical partition"
echo "[Enter]    - Accept logical partition"
echo "[Enter]    - First sector (default)"
echo "+500M      - Size of 500MB"
echo ""
echo "n          - Create logical partition"
echo "[Enter]    - Accept logical partition"
echo "[Enter]    - First sector (default)"
echo "+500M      - Size of 500MB"
echo ""
echo "p          - Print partition table"
echo "w          - Write changes and exit"

exercise_02.sh

instructional safe: yes requires: /dev/sdb

Download .sh View on GitHub

#!/bin/bash
# @type: instructional
# @requires: /dev/sdb
# @safe: yes

# Exercise 2: Convert partitions to LVM type if you used any other. From remaining space create another one.
#
# Task: Change partition types to Linux LVM (type 8e) and create additional partition.
#
# WARNING: This script requires a disk device. Use with caution!

echo "This script demonstrates the fdisk commands needed."
echo "Run: sudo fdisk /dev/sdb"
echo ""
echo "Commands to enter in fdisk:"
echo "t          - Change partition type"
echo "1          - Partition number 1"
echo "8e         - Linux LVM type"
echo ""
echo "t          - Change partition type"
echo "5          - Partition number 5"
echo "8e         - Linux LVM type"
echo ""
echo "t          - Change partition type"
echo "6          - Partition number 6"
echo "8e         - Linux LVM type"
echo ""
echo "n          - Create new partition"
echo "[Enter]    - Accept logical partition"
echo "[Enter]    - First sector (default)"
echo "[Enter]    - Last sector (use remaining space)"
echo ""
echo "t          - Change partition type"
echo "7          - Partition number 7"
echo "8e         - Linux LVM type"
echo ""
echo "p          - Print partition table"
echo "w          - Write changes and exit"

exercise_03.sh

executable safe: no requires: root, /dev/sdb

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root, /dev/sdb
# @safe: no
set -euo pipefail

# Exercise 3: Using the LVM partitions you created in a previous exercise, 
# create physical volumes and include into vg01 group.
#
# Task: Initialize LVM physical volumes and create a volume group.
#
# WARNING: This will format the specified partitions. Use with caution!

sudo pvcreate /dev/sdb{1,5,6,7}

sudo vgcreate vg01 /dev/sdb{1,5,6,7}

# Display the volume group information
sudo vgdisplay vg01

exercise_04.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 4: From the vg01 volume group, create a new logical volume named lv01 with a size of 3 GiB.
# Create a second logical volume named lv02 that uses 40% of the remaining free space in the volume group.
#
# Task: Create two logical volumes with different sizing methods.

sudo lvcreate -n lv01 -L 3G vg01

sudo lvcreate -n lv02 -l 40%FREE vg01

# Display the logical volumes
sudo lvdisplay vg01

exercise_05.sh

executable safe: no requires: root, /dev/sdb

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root, /dev/sdb
# @safe: no
set -euo pipefail

# Exercise 5: Delete all LVs and VG.
#
# Task: Clean up LVM configuration by removing logical volumes, volume groups, and physical volumes.
#
# WARNING: This will destroy data. Use with caution!

# Remove logical volumes
sudo lvremove /dev/vg01/lv0{1,2}

# Remove volume group
sudo vgremove vg01

# Remove physical volumes
sudo pvremove /dev/sdb{1,5,6,7}

echo "All LVM structures have been removed."

Chapter 6: Filesystems and Storage Answers

Mon, 01 Jan 0001 00:00:00 +0000

Topics

GPT partitioning (parted)
XFS filesystem
fstab configuration
SGID permissions
Swap files

exercise_01.sh

instructional safe: yes requires: /dev/sdb

Download .sh View on GitHub

#!/bin/bash
# @type: instructional
# @requires: /dev/sdb
# @safe: yes

# Exercise 1: Use the parted command to create a new GPT partition table on a disk (e.g., /dev/sdb) 
# and then create a new primary partition using 30% of the available space. 
# Format this partition with the XFS file system.
#
# Task: Create GPT partition table, partition, and format with XFS.
#
# WARNING: This will erase all data on the disk. Use with caution!

echo "This script demonstrates the parted commands needed."
echo "Run: sudo parted /dev/sdb"
echo ""
echo "Commands to enter in parted:"
echo "mktable gpt         - Create GPT partition table"
echo "mkpart primary xfs 0% 30%  - Create partition using 30% of space"
echo "print               - Display partition table"
echo "quit                - Exit parted"
echo ""
echo "Then format the partition:"
echo "sudo mkfs.xfs /dev/sdb1"

exercise_02.sh

executable safe: no requires: root, /dev/sdb

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root, /dev/sdb
# @safe: no
set -euo pipefail

# Exercise 2: Modify the /etc/fstab file to ensure the new XFS partition mounts automatically 
# to /mnt/newxfs every time the system boots. Use the partition's UUID for the entry.
#
# Task: Create mount point, get UUID, and add entry to /etc/fstab.

# Create mount point
sudo mkdir -p /mnt/newxfs

# Get the UUID of the partition
echo "UUID of /dev/sdb1:"
sudo blkid /dev/sdb1

# Add entry to /etc/fstab
# Get the UUID from blkid output and add to fstab
UUID=$(sudo blkid -s UUID -o value /dev/sdb1)
echo "UUID=$UUID /mnt/newxfs xfs defaults 0 0" | sudo tee -a /etc/fstab

# Verify fstab syntax
sudo findmnt --verify

# Reload systemd and mount
sudo systemctl daemon-reload
sudo mount -a

echo "Partition should now be mounted at /mnt/newxfs"

exercise_03.sh

instructional safe: yes requires: /dev/sdb

Download .sh View on GitHub

#!/bin/bash
# @type: instructional
# @requires: /dev/sdb
# @safe: yes

# Exercise 3: Use parted command to create a new partition with LVM type using 50% of the available space.
# Add partition to existing LVM group and extend / file system.
#
# Task: Create LVM partition, add to volume group, and extend root filesystem.
#
# WARNING: This modifies disk partitions and filesystems. Use with caution!

echo "This script demonstrates the parted and LVM commands needed."
echo ""
echo "Step 1: Create partition with parted"
echo "Run: sudo parted /dev/sdb"
echo "mkpart primary 30% 80%"
echo "set 2 lvm on"
echo "print"
echo "quit"
echo ""
echo "Step 2: Add to LVM"
echo "sudo vgextend rhel /dev/sdb2"
echo ""
echo "Step 3: Extend logical volume and filesystem"
echo "sudo lvextend -l +100%FREE /dev/rhel/root"
echo "sudo xfs_growfs /"

exercise_04.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 4: Use the lsblk --fs or blkid commands to list all file systems 
# on your system and their corresponding UUIDs.
#
# Task: Display filesystem information for all block devices.

echo "=== Using lsblk --fs ==="
sudo lsblk --fs

echo ""
echo "=== Using blkid ==="
sudo blkid

exercise_05.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 5: Create a directory /tmp/shared_project and a group named devops. 
# Set the directory's group ownership to devops and apply the SGID bit. 
# Add your user to the devops group and verify that any new files you create 
# in that directory inherit the devops group ownership.
#
# Task: Create directory with SGID bit, configure group ownership, and test inheritance.

# Create directory
sudo mkdir -p /tmp/shared_project

# Create group
sudo groupadd devops

# Set group ownership
sudo chgrp devops /tmp/shared_project

# Set permissions with SGID bit (2770)
sudo chmod 2770 /tmp/shared_project

# Add current user to devops group
sudo usermod -aG devops "$USER"

# Display directory permissions
ls -ld /tmp/shared_project/

# Switch to devops group context
newgrp devops << EOF
# Create a test file
touch /tmp/shared_project/testfile

# Verify group ownership
ls -l /tmp/shared_project/testfile
EOF

echo ""
echo "Verification complete. The testfile should have devops group ownership."

exercise_06.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 6: Create a 1 Gb file at /tmp/swapfile using dd. 
# Use the mkswap command to format the file as a swap area. 
# Activate the swap file with the swapon command and verify the new total swap size with free -h.
#
# Task: Create and activate a swap file.

# Create 1 GB swap file
sudo dd if=/dev/zero of=/tmp/swapfile bs=1M count=1024

# Set proper permissions (important for security)
sudo chmod 600 /tmp/swapfile

# Format as swap
sudo mkswap /tmp/swapfile

# Activate swap
sudo swapon /tmp/swapfile

# Verify swap is active
free -h

echo ""
echo "Swap file created and activated. Use 'sudo swapoff /tmp/swapfile' to deactivate."

Chapter 7: System Management Answers

Mon, 01 Jan 0001 00:00:00 +0000

Topics

Systemd targets
Journal logs
Process management (ps, nice, renice)
TuneD profiles

exercise_01.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 1: Use systemctl to find the default systemd target on your system. 
# Use systemctl to temporarily switch your system to multi-user.target.
#
# Task: Display current default target and switch to multi-user target.

echo "Current default target:"
systemctl get-default

echo ""
echo "Switching to multi-user.target..."
sudo systemctl isolate multi-user.target

echo ""
echo "System is now in multi-user.target mode."

exercise_03.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 3: Examine the output of journalctl -b to review the messages from the most recent system boot.
#
# Task: Display system journal entries from the current boot.

sudo journalctl -b

exercise_04.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 4: Use the ps command to identify the top 3 processes consuming the most CPU and memory.
#
# Task: List processes sorted by CPU and memory usage.

echo "=== Top 3 CPU-consuming processes ==="
ps aux --sort=-%cpu | head -n 4

echo ""
echo "=== Top 3 Memory-consuming processes ==="
ps aux --sort=-%mem | head -n 4

exercise_05.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 5: Start a new process with a non-default nice value using the nice command, 
# and then verify the change with ps.
#
# Task: Start a process with modified priority and verify it.

# Start sleep process with nice value of 10
nice -n 10 sleep 3600 &

PID=$!
echo "Started sleep process with PID: $PID and nice value 10"

# Verify the nice value
echo ""
echo "Process information:"
ps lax | grep sleep | grep -v grep

exercise_06.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 6: Use renice to change the niceness of a running process, 
# and then confirm the change with ps.
#
# Task: Modify the priority of an already running process.

# First, we need a process to renice
# Start a sleep process in background
sleep 3600 &
PID=$!

echo "Started process with PID: $PID"
echo ""
echo "Original priority:"
ps lax | grep $PID | grep -v grep

# Change the nice value to 15
echo ""
echo "Changing nice value to 15..."
renice -n 15 $PID

# Verify the change
echo ""
echo "New priority:"
ps lax | grep $PID | grep -v grep

echo ""
echo "To kill this process, run: kill $PID"

exercise_07.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 7: Use tuned-adm active to determine which performance profile is currently active on your system. 
# Switch the active TuneD profile to throughput-performance using the tuned-adm profile command.
#
# Task: Check current TuneD profile and switch to throughput-performance.

echo "Current active TuneD profile:"
tuned-adm active

echo ""
echo "Switching to throughput-performance profile..."
sudo tuned-adm profile throughput-performance

echo ""
echo "New active profile:"
tuned-adm active

Chapter 8: Task Scheduling and Remote Access Answers

Mon, 01 Jan 0001 00:00:00 +0000

Topics

Background jobs
at command
Cron jobs
Time management (timedatectl)
SSH key generation and configuration

exercise_01.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 1: Execute the sleep 1200 command in the background. 
# Immediately verify it is running, and then note its job number.
#
# Task: Start a background job and verify its status.

# Start sleep in background
sleep 1200 &

echo "Sleep process started in background."
echo ""

# List jobs with PID
jobs -l

exercise_02.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 2: Start a ping 127.0.0.1 process in the foreground. 
# Stop it using the appropriate key sequence, and then send the stopped process 
# to the background so it resumes running.
#
# Task: Demonstrate job control - stopping and backgrounding a process.

echo "Starting ping in foreground..."
echo "Press Ctrl+Z to stop it, then run: bg %1"
echo ""

# Start ping process
ping 127.0.0.1

# After Ctrl+Z is pressed, the user would run:
# jobs
# bg 1
# jobs

exercise_03.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 3: Schedule a command using at to execute 5 minutes from now. 
# The command should redirect the output of date to a file named ~/test_output.txt.
#
# Task: Schedule a one-time task using the at command.

# Schedule the job
at now + 5 minutes << EOF
date > ~/test_output.txt
EOF

echo "Job scheduled to run in 5 minutes."
echo "The output will be saved to ~/test_output.txt"

exercise_04.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 4: Immediately after scheduling the job, use the command to view the job queue.
#
# Task: Display scheduled at jobs.

atq

exercise_05.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 5: Edit your user's crontab file to run the command 
# /bin/echo "Cron!" > ~/cron.log every day at 9:00.
#
# Task: Create a cron job that runs daily at 9 AM.

echo "Adding cron job..."

# Add the cron job
(crontab -l 2>/dev/null; echo "0 9 * * * /bin/echo \"Cron!\" > ~/cron.log") | crontab -

echo ""
echo "Current crontab:"
crontab -l

exercise_06.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 6: Use the Systemd utility to display the current system time, 
# time zone, and the status of the NTP service.
#
# Task: Display time and NTP synchronization status.

timedatectl

exercise_07.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 7: Generate a new key pair. Use a strong passphrase for security. 
# What are the names of the two files created in your ~/.ssh/ directory?
#
# Task: Generate SSH key pair and identify the created files.

echo "Generating SSH key pair..."
ssh-keygen -t ed25519 -f ~/.ssh/id_ed25519

echo ""
echo "Files created in ~/.ssh/:"
ls -la ~/.ssh/id_ed25519*

echo ""
echo "The two files are:"
echo "1. id_ed25519 (private key)"
echo "2. id_ed25519.pub (public key)"

exercise_08.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 8: You need to enable key-based authentication for the user root on the local server 127.0.0.1. 
# Use the specialized utility to securely copy your users' public key to the server.
#
# Task: Copy SSH public key to remote server for key-based authentication.

ssh-copy-id -i ~/.ssh/id_ed25519.pub root@127.0.0.1

echo ""
echo "Note: This will work if PermitRootLogin is enabled in the SSH server configuration."
echo "For a separate VM, you may need to modify /etc/ssh/sshd_config:"
echo "  PermitRootLogin yes"

exercise_09.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 9: Which two lines would you modify in the main OpenSSH server configuration file 
# (/etc/ssh/sshd_config) to disable password authentication and prevent the root user 
# from logging in directly?
#
# Task: Display the SSH configuration changes needed for improved security.

echo "To disable password authentication and prevent root login,"
echo "modify these lines in /etc/ssh/sshd_config:"
echo ""
echo "PasswordAuthentication no"
echo "PermitRootLogin no"
echo ""
echo "After making changes, restart sshd:"
echo "sudo systemctl restart sshd"

Chapter 9: Package Management Answers

Mon, 01 Jan 0001 00:00:00 +0000

Topics

DNF operations
RPM queries
Repository management
Flatpak applications

exercise_01.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 1: Use DNF to search for packages related to the "network" term, 
# listing only packages that are not yet installed.
#
# Task: Search for available network-related packages.

sudo dnf list available *network*

exercise_02.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 2: Install the zsh package using DNF, ensuring the installation proceeds 
# without any interactive prompts.
#
# Task: Install zsh package non-interactively.

sudo dnf install -y zsh

exercise_03.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 3: Remove the zsh package and any dependencies that are no longer needed, 
# using a single DNF command.
#
# Task: Uninstall zsh and clean up unused dependencies.

sudo dnf remove -y zsh

exercise_04.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 4: Display a detailed description and list of packages (mandatory, default, and optional) 
# included in the "Legacy UNIX Compatibility" package group.
#
# Task: Show information about a package group.

sudo dnf group info "Legacy UNIX Compatibility"

exercise_05.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 5: Determine which installed RPM package owns the /etc/filesystems file.
#
# Task: Find the package that provides a specific file.

rpm -qf /etc/filesystems

exercise_06.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 6: Use the rpm command to list all files included in the installed bash package.
#
# Task: Display all files provided by the bash package.

sudo rpm -ql bash

exercise_07.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 7: Use the dnf config-manager utility to enable the 
# codeready-builder-for-rhel-10-x86_64-rpms repository.
#
# Task: Enable a DNF repository.

sudo dnf config-manager --enable codeready-builder-for-rhel-10-x86_64-rpms

exercise_08.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 8: Install virt-manager package.
#
# Task: Install the virt-manager virtualization management tool.

sudo dnf install -y virt-manager

exercise_09.sh

executable safe: yes

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: none
# @safe: yes
set -euo pipefail

# Exercise 9: Write the flatpak command to add the Flathub remote repository only 
# for the current user, without system-wide privileges, and only if the remote doesn't already exist.
#
# Task: Add Flathub repository for user-level flatpak installations.

flatpak remote-add --user --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo

echo "Flathub repository added for current user."

exercise_10.sh

executable safe: no requires: root

Download .sh View on GitHub

#!/bin/bash
# @type: executable
# @requires: root
# @safe: no
set -euo pipefail

# Exercise 10: Install Gimp from Flathub.
#
# Task: Install the GIMP image editor using flatpak.

flatpak install flathub org.gimp.GIMP

echo "GIMP has been installed via Flatpak."

Practice Lab: Installing RHEL 10 in a VM

Mon, 01 Jan 0001 00:00:00 +0000

What you need

Most exercises in this companion repo assume a single throwaway machine running Red Hat Enterprise Linux 10. A practical starting point is 2–4 virtual CPUs, at least 1.5 GiB RAM, and 10 GiB disk. A few storage topics are easier with a second disk (many answer scripts refer to `/dev/sdb`), but you can still practice on one VM if you attach an extra virtual disk later.