Linux multi-distro training script

linux_trainer.sh

#!/bin/bash

hshu="867d90e6f81e9bf68a7f1690e451fa4e96df8944140d4a3b671216eac4cd4975"
hshp="26a1600d38754149cc9cebdae6826dd4740a9dcb2aa4cb5f7cd09bde42abbab4"

print_with_delay() {
    local text="$1"
    local delay=0.04

    for (( i=0; i<${#text}; i++ )); do
        echo -n "${text:$i:1}"
        sleep $delay
    done
    echo
}

authenticate_user() {
    read -p "Username: " unme
    read -sp "Password: " pwrd
    echo

    ehshu=$(echo -n "$unme" | openssl dgst -sha256 | cut -d' ' -f2)
    ehshp=$(echo -n "$pwrd" | openssl dgst -sha256 | cut -d' ' -f2)

    if [ "$ehshu" != "$hshu" ]; then
        exit 1
    fi

    if [ "$ehshp" != "$hshp" ]; then
        exit 1
    fi
}

select_and_start_container() {
    echo ""
    echo -e "\e[33mLinux Training Module\e[0m"
    echo -e "\e[33m----------------------------------\e[0m"

    print_with_delay "Hello user! Lets train."

    echo ""
    echo ""

    read -p "Would you like to take a crash course before hopping in your Linux environment? (y/N) " response
    case $response in
        [yY][eE][sS]|[yY])
        crash_course
        ;;
        *)
        echo "Skipping crash course."
        ;;
    esac

    valid=false
    while [ $valid == false ]; do
        echo ""
        echo "Please select a Linux distribution:"
        echo "1) Debian"
        echo "2) Rocky"
        echo "3) CentOS"
        echo "4) Ubuntu"
        echo "5) Fedora"

        read -r -p "Enter your choice [1-5]: " choice

        if [[ $choice =~ ^[1-5]$ ]]; then
             valid=true
             else
                 echo "Invalid selection. Please choose between 1 and 5."
        fi
    done

    case $choice in
      #1) image="debian:latest" ;;
      #2) image="rockylinux/rockylinux:latest" ;;
      #3) image="centos:latest" ;;
      #4) image="ubuntu:latest" ;;
      #5) image="fedora:latest" ;;
      1) image="debian:buster-slim" ;;
      2) image="rockylinux/rockylinux:8-minimal" ;;
      #3) image="quay.io/centos/centos:stream8" ;;
      3) image="dokken/centos-stream-9" ;;
      4) image="ubuntu:22.04" ;;
      #5) image="fedora:rawhide" ;;
      #5) image="fedora:38" ;;
      5) image="dokken/fedora-40" ;;
    esac

    echo ""
    #docker run -it --rm --read-only --user mountaineer --tmpfs /tmp --tmpfs /home/mountaineer --tmpfs /var/cache/apt "$image" /bin/bash -c "cat /etc/os-release; exec /bin/bash"
    docker run -it --rm --network=none --memory="256m" --cpus="0.5" --pids-limit=50 "$image" /bin/bash -c "cat /etc/os-release; exec /bin/bash"
}

crash_course() {
    echo ""
    echo -e "\e[33mMountaineer Linux Crash Course\e[0m"
    echo -e "\e[33m----------------------------\e[0m"

    print_with_delay "The Linux operating system is an open source operating system."
    print_with_delay "To interact with the kernel, filesystem, and files, Linux provides a command line interface."
    print_with_delay "To empower you in the Linux environment, we will learn some commands"
    echo ""

    declare -A commands
    commands["pwd"]="The pwd command prints the current working directory."
    commands["ls -l"]="The ls command lists files and directories in the current directory."
    commands["whoami"]="The whoami command displays the username of the current user."

    for cmd in "${!commands[@]}"; do
        print_with_delay "${commands[$cmd]}"
        echo -n "Please try out the $cmd command now: "
        read input
        if [ "$input" == "$cmd" ]; then
            echo "Perfect!"
            echo ""
        else
            echo "Not quite, but all good. You got the idea."
            echo ""
        fi
    done
    echo "Crash course completed."
}

authenticate_user
select_and_start_container