Mastering Linux System Administration and Troubleshooting

Compare Windows, Linux, and Unix operating systems, focusing on server versus client roles and popular flavors. Learn rpm-based and Debian-based packaging, from Red Hat to Ubuntu and Kali.

Set up a virtual lab by installing a Linux OS in VirtualBox, choosing Debian-based or rpm-based distributions, and cloning golden images for safe practice.

Explore downloading preconfigured virtual machines from OS boxes for VirtualBox, including CentOS and other popular Linux images; learn how to set up a ready virtual machine quickly.

Create a fresh CentOS nine VM in VirtualBox, set up a base template, then clone it to Jenkins, Ansible, and web apps, configure SSH, network bridging, and static IPs.

Configure a dhcp-enabled interface to ensure automatic ip assignment on reboot for all cloned virtual machines, saving the startup command in the interface file.

Learn to download and install Ubuntu in VirtualBox, choose a compatible Ubuntu image, create a fresh VM, configure network bridging, and set up a new user and root access.

Install and enable openssh-server on ubuntu, start sshd, and verify ssh access by ip, connecting as a user or root, then optionally set a hostname.

Learn how to install OpenSSH on Linux, enable ssh access, learn about port 22, and harden root login; connect from Windows using cmd, PowerShell, PuTTY, or MobaXterm.

Transfer files between Linux, Unix, and Windows using FTP, SFTP, or SCP with FileZilla, including upload and download workflows.

Understand data center infrastructure, including physical servers, production deployments, and cloud versus datacenter setups. See how active and passive data centers and Linux clustering enable automatic failover and disaster recovery.

Discover application staging across environments—from development and internal testing to staging, UAT, and production—using git, automation tools, and containers to test, verify, and promote code.

Explore shell terminals and why Bash remains the default for system administration. Compare Bash with Z shell, Fish, Ksh, Csh, and Tcsh, and cover basic shell checks and autocomplete benefits.

Explore the file system hierarchy from the root slash, learn absolute paths, and see how mounting a disk creates a new branch under root.

Master the pipeline concept in Linux command line, chaining commands to filter outputs, using grep and other tools to refine results across scripts and tasks.

Discover the essential daily command used across Linux, Unix, and Mac to inspect system status, with common options for ls, cd, mv, and basics on disk management, networking, and patching.

Learn essential linux commands with man and ls, including -l, -a, -h flags, hidden files, and sorting by time or size to distinguish files from directories.

Navigate the filesystem with cd and pwd, noting root permissions. Copy, move, and remove with cp, mv, and rm using -r, -i, -p, and -f; create with mkdir and touch.

Learn the power of grep for debugging and searching files across directories, using -i, -r, -l, -n, -w, -a, -b, and -v to find words, IPs, and patterns.

Master essential linux commands, including df with -h, -t, and -A for disk usage and file system type, and use cat, grep, and tail -f for viewing and live logging.

Learn how to edit files on Linux using Vim and Nano, comparing vi compatibility, insert mode basics, and essential save, quit, and navigation commands.

Redirect command output to a file using > for stdout and >> to append, and redirect errors with 2> or send them to /dev/null.

Explore Linux permissions and file types by examining ls -l output, identifying owner, group, others, and the nine-character indicator for file, directory, or link.

Explore Linux file permissions for user, group, and others, and learn read, write, and execute bits while practicing symbolic chmod with u, g, and o.

Learn how Linux permissions map to numbers: read 4, write 2, execute 1 for user, group, and others. Use numeric chmod such as 644 and 755, and beware -R.

Learn how to manage file ownership and permissions on Linux by using chown and chmod, including owner and group assignments, recursive changes, and demonstrations with a superuser.

Locate running processes with ps, monitor activity via top, and terminate unwanted ones using kill (graceful or -9), while filtering for targets like httpd with grep and ps.

Manage Unix permissions by organizing users into groups and assigning access to directories. Create groups, add or remove members, and apply permissions by group to simplify administration.

Create and delete users and groups, and manage primary and secondary groups. Assign fixed uid and gid for cross-server consistency, and verify membership using /etc/group and /etc/passwd.

Switch to other users with the su command, with or without dash, and learn that root can switch to any user without a password while others must authenticate.

Master Linux sudo basics: grant users or groups selective root privileges via the sudoers file, with password prompts, logging, and best practices using visudo.

Learn to manage services with systemctl; check status, reload or restart, and enable or disable them. The module covers sshd and httpd, unit files, and basic firewall considerations.

Create a custom systemd service by writing a hello world script, making it executable, defining a unit with description and exec start, then enable and check its status with systemctl.

Explore how network concepts drive Linux server setup, including NIC interfaces, IP addresses, gateways, routers, and switches, and compare physical and virtual NICs in real and virtual environments.

Mastering Linux network administration through NetworkManager and nmcli, this lecture teaches configuring IPs, gateways, and DNS—static vs dynamic—across multiple interfaces using manual and NetworkManager methods.

learn to configure linux network interfaces using network manager and manual files, set static or dynamic ip, manage gateways, rename devices and connections, troubleshoot duplicates, and implement bonding.

Explain how dns translates human readable names to ip addresses, compare local host files with dns servers, and highlight keeping data both locally and in dns for reliability and performance.

Learn how Linux resolves names using /etc/resolv.conf and /etc/hosts, and manage DNS with Network Manager or manual config across Ubuntu and CentOS.

Learn to configure network bonding to combine multiple NICs into a single virtual interface, delivering high availability and improved throughput via master and slave setups and nmcli configuration.

Explore how software firewalls are often disabled in favor of physical appliances, and learn how to check, stop, and mask a firewall with systemctl while considering DMZs and port openings.

Learn how ports differentiate services on an IP, such as http on 80 and ssh on 22, and how containers map port 80 to the server with apache or nginx.

Master Linux firewall commands to open and close ports with firewall-cmd, verify with netstat and telnet, and configure Apache to listen on port 80.