Learn Linux administration and linux command line skills

Learn how to download and install Oracle VirtualBox on Windows, from selecting Windows hosts to finishing the setup and launching the Oracle VM VirtualBox application.

Download CentOS Linux from centos.org and choose the dvd iso for a full installation. The current version is 7.6, and the iso downloads to your downloads folder for installation.

Install CentOS 7 on Oracle VM VirtualBox by creating a Linux VM, mounting the CentOS 7 ISO, configuring a network bridge, and selecting GNOME desktop.

Download and install the PuTTY client from putty.org, choose the 64-bit or 32-bit version, and connect by entering the server IP and logging in with your user ID and password.

Download Suse Linux Enterprise Server 12 SP3 for amd64 using a 60-day free trial, create an account, sign in, and obtain the ISO DVDs.

Install SLES 15 in a virtual machine using Oracle VM VirtualBox, configure VM settings, choose a minimal text-mode install, create a user and root access, and verify network connectivity.

Install SLES 12 SP3 in VirtualBox using expert partitioning to create boot, root, and LVM volumes with ext4, including swap, /var, /home, and /tmp, and set up a user administrator.

Learn multiple methods to access your Linux server, including booting in Oracle VM VirtualBox, logging in via the terminal, using PuTTY, and SSH into other servers.

Download and install Red Hat Enterprise Linux 9.2 on VirtualBox, choose x86_64, configure a VM with 2 GB RAM, 2 CPUs, and 25 GB disk from the DVD ISO.

Install Kali Linux in a VirtualBox VM by meeting hardware requirements, downloading the 64-bit ISO, and performing a graphical install from the Kali website.

Explore the linux directory structure and its filesystem hierarchy, learning the roles of /boot, /root, /dev, /etc, /bin, /proc, /lib, /tmp, /home, /var, and /usr/local.

Explore the shell as the command interpreter between user and kernel, handling instructions and returning results, with bash features like variable manipulation, redirection, history, and tab completion.

Master essential Linux commands and terminal navigation with cd, ls, cat, pwd, and more, and understand case sensitivity, manual pages, and practical admin workflows in the command line.

Learn to list directory contents with ls and ls -l, read metadata like permissions, owner, group, size, and date, and use -a, -h, -t, and -F to identify file types.

Learn to change your own password with the passwd command, while root can reset other users' passwords, and understand how system password policies affect password requirements.

Learn the differences between absolute and relative paths, starting with a slash for absolute paths and dependence on the current directory for relative paths, with cd and pwd examples.

Find help at the command line with Linux man pages, info, keyword searches via man -K, and quick whatis lookups.

Learn how to create files with touch and vi editors, including multiple files and timestamp updates, and create directories with mkdir, including nested hierarchies using the -p option.

Learn to modify file and group ownership in Linux, using chown and chgrp, including single-file and recursive directory changes with the owner:group format and user creation via useradd.

Learn the vi editor basics, its command, insert, and line modes, and essential editing tasks like creating, saving, copying, deleting, undoing, searching, and substituting text.

Learn how the cp command copies files and directories, including recursively copying a directory from dir one to dir two, and understand the default overwriting behavior with the -i option.

Learn to use more and less to view large files, paging by page or line with enter or space, search with slash, and quit with q.

Use head and tail to view the first or last lines of files, with defaults of 10 lines, options like -4, and real-time log monitoring with tail -F.

Learn tab completion in bash to speed up entering files, directories, and commands. Press tab once to complete, twice to view options, and navigate long names.

Learn how wild cards (metacharacters) enable pattern matching in Linux commands, including the asterisk, question mark, and square brackets, with practical terminal examples.

Learn how inode metadata and the kernel assign numeric identifiers to files. Soft links become useless if the original file is deleted; hard links share the same inode.

Explore bash input, output, and error redirection using <, >, and >>, with examples of reading from a file, overwriting or appending output, and redirecting errors.

Master grep, a command line tool for searching plain text with regular expressions and printing matching lines. Use -i, -n, and -v to see case sensitivity, numbering, and exclusions.

Create and use shell aliases to shorten frequent commands in bash, test and view aliases with the alias command, and make them permanent by editing the current user's bashrc file.

Master the echo command in Linux to display text, output to the screen or a file, and use it in shell scripts and with variables.

Explore environment variables, how to define, export, and unset them, and distinguish local vs environment variables. See how PWD, hostname, and PS1 affect the shell prompt and behavior.

Learn to connect between servers using SSH with an IP or hostname, log in with a password, and exit; when using the same username you can omit it for simplicity.

Transfer and copy files over the network using scp and sftp, both part of the ssh suite, to securely move files between servers and verify in /tmp.

Learn to use the wc command to count lines, words, and characters in a file, and use -L, -W, -C or -M options.

Learn to view and monitor linux processes with ps and top, reading columns like pid, uid, time, and cmd, and watch real-time load, memory, and swap to troubleshoot performance.

Schedule and automate tasks with cron and crontab to run backup scripts or commands at specific times, using five asterisks for minute, hour, day, month, and weekday.

Master user and group administration using commands like user add, user del, group add, and user mod to create, delete, and modify accounts, then verify with id and /etc/passwd.

Learn to switch users in Linux with su and su -, compare environment changes and startup scripts, and avoid logging in as root on live systems.

Master the sudo utility to grant privileged access and run commands as root. Edit the sudoers file to assign user and group rights, including no-password options and restricted command sets.

Learn to compress and archive files and directories using gzip, gunzip, and bzip2, and to create, list, and extract tarballs with tar options.

Display and set the hostname with hostname and hostnamectl; view static hostname, VM details, machine ID, boot ID, kernel, and architecture. Make changes permanent by rebooting or editing /etc/hostname.

translate characters with tr, sort, diff, and uniq for practical text file manipulation in linux.

Learn to extract fields with cut using a delimiter and sort the results, demonstrated by piping tail to cut to list usernames from the password file and sort them.

Compare 32-bit and 64-bit operating systems, focusing on memory limits (4 gigabytes vs 16 exabytes) and compatibility. Check architecture with arch or uname -m, and favor 64-bit for better performance.

Learn how to recover a forgotten Linux root password by booting into single-user mode, editing grub, using passwd, and triggering autorelabel before reboot.

Learn how to install and run sosreport for Red Hat troubleshooting. Generate a diagnostic archive and upload it to Red Hat support for initial analysis.

Learn to monitor Linux system activity by using commands like id, who, last, and w to view user IDs, groups, current logins, last logins, and process activity.

Learn how to configure motd files to display login messages and monitor company policies. Use the wall command to broadcast notices to all logged-in users, such as reboot warnings.

Learn how to manage software on Red Hat, CentOS, and Fedora using yum, including install, update, remove, and automatic dependency resolution, plus search, group install, downloading, and history.

Learn rpm package management for Red Hat, CentOS, Fedora, and Suse Linux distributions, including install, upgrade, remove, verify, and query commands, plus package info, locations, and dependency handling with yum.

Explore repositories in Linux, learn how yum uses enabled repositories, base URLs, and mirror lists to install software from online or local repos such as the EPL repo on CentOS.

Learn to create a local repository on most Linux distributions, using CD/DVD or downloaded packages, disable current repos, and install software from the local repo.

Learn how to prepare for Linux system updates by choosing yum update to preserve old packages, using version lock to freeze software, protecting repositories, and applying targeted or security updates.

Master rolling back patches and updates with snapshots and backups on virtual and physical servers, using yum history undo and downgrade options to return to a previous state.

Use zypper on SUSE Linux to install, remove, and update packages from the command line. Learn to patch packages, list installed packages, view information, and search for items like NTP.

Learn how to install, remove, update, and upgrade software in Ubuntu using apt-get, search the package index, and manage deb and deb-src packages.

Master user and group administration on Linux by creating, deleting, and modifying users and groups, using commands like useradd, userdel, groupadd, and usermod, and checking results with id and grep.

Learn how to create a user account with no login access using a no-login shell for application accounts. Verify the shell in /etc/passwd and test login denial by switching users.

Learn how to use the passwd command to change passwords, lock and unlock user accounts, and set expiry dates, with examples of normal users, root, and sudo privileges.

View and adjust password aging for user accounts using change -L to inspect current settings, and set min days (-n), max days (-x), and warning days (-W) for specific users.

Activate the shadow password mechanism with pw conf and grp conv to create root owned shadow files; deactivate with the same tools, referencing Etsy login file for password aging attributes.

Explore the passwd file and its seven colon-separated fields that describe each user account. See terminal examples, learn that root has UID 0, and understand home directories and default shells.

Explore the shadow file and shadow password mechanism, understanding how secure local passwords, expiration, and per-user limits are stored and enforced.

Discover how the group file stores group information, with each line as a group entry, and how a user’s primary group and membership appear in the group and passwd files.

Switch users in linux with su and su -, understand why root logins are discouraged, and see how environment and home directory change when you switch.

Learn how the sudo utility lets normal users run privileged commands, manage access via the sudoers file, and grant all or restricted privileges, including no-password configurations.

Explore how disk partitions and file systems organize data across Windows and Linux, compare MBR and GPT, boot processes, and learn partitioning tools like fdisk, parted, gdisk, and LVM.

Explore the logical volume manager (LVM), which provides an abstraction layer between physical storage and the file system, enabling resizing, spanning multiple disks, and moving data without downtime.

Learn to manage storage with the parted tool in Linux, creating and deleting MBR or GPT partitions, checking disk labels, and using basic commands in the terminal.

Create a physical volume on /dev/sdb. Build a volume group named test_vg and a logical volume example_lv. Format with ext3, mount to /tmp/example, and update /etc/fstab for persistence.

Use pv create and vg extend to add a disk, then lv extend and resize the file system while the logical volume is mounted.

Learn to create a mirrored logical volume with lvm on two disks in a raid-1 arrangement, format as ext4, mount it, and enable permanent mounting in /etc/fstab.

Move volumes from one storage to another by extending the volume group, moving the physical volume with pv move, and then removing the old disk to reclaim space.

Unmount and remove a logical volume, then delete its volume group and the physical volume using lvremove, vgremove, and pvremove. Verify the deletions with pvs, vgs, lsblk, and lvs.

Learn how shell scripting automates command sequences in a shell or container by writing a script that runs commands like pwd in a loop, saving time.

Create a dedicated scripts directory, name each shell script by its function, and use mv to rename with a .bash extension for bash, or appropriate shell extensions.

Learn to structure shell scripts with a clear format using bash, including comments, variables, and echo. Create and run a format-script that prints a variable and the current path.

Learn how to run a shell script by creating a script file and executing it with the dot sign and a forward slash, or with the script name.

Learn the vi editor basics in Linux, including command, insert, and line modes, creating and editing files, saving with :wq, and using copy, paste, undo, redo, search, and substitute commands.

Learn to create your first bash script that echoes Hello World, save it, grant executable permissions with chmod +x, run it with ./script, and practice printing your name.

define variables in shell scripting, assign string or command values, and print them with echo; understand simple versus command stored variables and run a script with executable permissions.

Learn bash arithmetic operators, including addition, subtraction, multiplication, division, modulus, and exponentiation. Watch increment and decrement by constants with double parentheses in a script using a and b.

Explore string manipulation in shell scripting by defining string variables with or without quotes, printing methods with echo, measuring length using ${#var}, and concatenating strings.

Learn string comparisons in shell scripting, using equal and not equal operators, hyphen z and hyphen n for length checks, demonstrated with a bash script using x, y, and z.

Learn to write a bash script that uses read to capture user input and echo to display a personalized welcome, demonstrating variables like user_name.

Explore network components such as ip address, subnet mask, gateway, static ip versus dhcp, ethernet and a virtual interface, and mac address.

Explore how IP addresses are organized into network and host portions, and examine class A, class B, and class C networks with their ranges and default subnet masks.

Explore TCP and UDP protocols on the transport layer, contrast connection-oriented TCP with guaranteed data delivery and fast, connectionless UDP, including the three-way handshake.

Explore the OSI model as a seven-layer framework for networking, covering application, presentation, session, transport, network, data link, and physical layers, with real-world troubleshooting guidance.

Explore Linux network interfaces, configuration files, and commands. Configure NICs and bonding for redundancy, IPv4/IPv6 with ifcfg files, hosts, resolv.conf, and nsswitch.conf, using nmcli or ip commands.

Find your IP address using hostname -I, and use ip addr to view interfaces and the loopback address, noting distro differences for CentOS or Red Hat.

Learn to configure nic bonding with two interfaces, load the bonding driver, create bond0 in round-robin mode, assign IP 192.168.1.120 and gateway 192.168.1.1, and verify via network manager.

Install and configure the Apache httpd web server, edit httpd.conf, create an index.html in /var/www/html, start the service, and verify access via elinks on localhost.

Learn to install and configure a lamp stack on Linux, enabling and starting Apache and MySQL (or MariaDB), installing PHP, and verifying versions.

Learn to install and secure MySQL server on Linux, create the academy database and knixwear user, grant privileges, and perform basic crud on a students table.