Linux Troubleshooting Essentials: Tech Exam Prep for IT Skills Development

In this episode of Technology Tap: CompTIA Study Guide, we dive into essential Linux troubleshooting techniques vital for IT skills development and tech exam prep. Understanding how to diagnose system issues is crucial when preparing for your CompTIA exams and enhancing your practical IT abilities. We explore how to view the system as a dynamic set of processes, using tools like ps and top to monitor CPU and memory usage in real-time. Learn why process IDs (PIDs) matter and how to effectively manage problematic processes with commands like kill and kill -9. We also cover managing system services properly with systemctl to check statuses, start stopped services, and halt errant processes. Whether you're studying alone or in a study group, these insights serve as a valuable part of your CompTIA study guide, equipping you with hands-on knowledge for technology education and IT certification success.

Then we zoom out to the tools that keep Linux stable in the real world: package managers like apt and dnf/yum for verified software installs, plus network troubleshooting with ping for connectivity and dig for DNS resolution. We also talk about cron automation, because scheduled tasks can be your best friend or the hidden cause of recurring issues.

To round it out, we compare Linux’s exposed control with macOS design choices: Finder, Dock, and Spotlight for speed, while still keeping a Unix foundation underneath. We hit key macOS security and recovery features like FileVault, Keychain, and Time Machine, and we close with CompTIA-style practice questions to lock in the concepts. Subscribe, share this with a friend studying A+, and leave a review with the command you want us to cover next.

Transcript

Welcome And Book Recommendation

SPEAKER_01 0:26

Hey and welcome to the final detail. I'm Professor Jay Wall. In this episode, we're gonna talk about Linux. Professor J. Rod. For those of you who don't know me, I'm a professor of cybersecurity and I like helping my students pass their A Plus, Network Plus, and Security Plus series of exams. I'm also wrote the book Scam Proof for Life. Right to help seniors. Sorry, Scam Proof for Seniors. I say Scam Proof for Life. No, Scam Proof for Seniors to help you know your mom, dad, grandma, grandpa, uncle, aunt help them not get scammed. Because you know there's a lot of scammers out there. You can find that on Amazon. It's called Scam Proof for Seniors, written by me, Dr. Rodriguez. And or you can find it at my website, Professor Jrod. That's J R O D dot com slash books, and you will see it there. And you can order it at professorjrod.com. Yeah, it's a good book. Buy it, you know, support the show, support me, and help out your parents, grandparents, all that makes a great Mother's Day gift, by the way. Mother's Day is a few weeks away, so you know if you don't know what you want to buy your mom or grandma for Mother's Day. This is a perfect Mother's Day gift that you can buy. Again, it's on Amazon if you want a scan proof for seniors. Or you can, you know, buy Dr. Rodriguez. Scan proof for seniors, how to recognize, avoid, and stop modern scans. You can buy it on Amazon or on professorjrod.com slash books. Alright. So this is part two. Oh also I'm also on social media, as you know. I'm on TikTok at Professor J Rod, Instagram at Professor J Rod, and the Facebook Technology Tap Podcast. So, all right, so let's move forward. Picking up from last episode, right, where we talked about where I am and as far as Linux is concerned and who is allowed to act. Right now we reach the next question. What is the system actually doing right now? You need to understand who has permission for what, right? For permissions alone don't tell you what's happening. A system has correct permissions, can have a valid users, and have proper structure, and still fail. Why? Because something is actively running incorrectly. So the question is, what is the system doing right now? And is that behavior correct? Because operating systems are not static, they are collections of active processes. So a process is a program that is currently running in memory. Example, a web browser, a background service, a system task, a malicious program. Why does this matter? Because problems are rarely, you know, like this file exists. They are always something is using, is using, blocking, or breaking that file. Users see apps, windows, and icons, and you as a technician should be seeing processes interactive with resources. So your first tool that you're gonna run in Linux to see what's running is the PS command. PS command displays a snapshot of current running processes. So, for example, if you ps space AUX, what this shows? It shows the user who owns the process, the process ID, the usage, the CPU usage, memory usage, and the command when it's running. Why is this important? Because it answers what exists at this exact moment. Next to is the top command, TOP, displays real-time system activity. Right? What do you see when you type in top? You see live CPU usage, memory consumption, running processes, and system loads. What's the difference between PS and top? PS is a snapshot and top is live monitoring. And why does this distinction matter? Because troubleshooting depends on if the problem is consistent or dynamic. In the real world, the users say my computer's slow, right? The wrong approach is to restart, guess, or blame hardware. But truth be told, restart helps a lot. Right? Technician approach, you hit top, you observe that the CPU is at 100%, and you have one process consuming resources. The issue is not the system, it's a specific process behaving bad. Next, you have a PID, right? Process ID is a unique number assigned to each process. Why does it matter? Because you don't stop programs by name, you stop them by identity. Kind of like task manager, right? Or task kill.

unknown 6:22

Right?

Killing Processes And Managing Services

SPEAKER_01 6:23

This is the kill command, sends a signal to terminate a process. Right? If you've done task kill in Windows, it's similar, right? You just do the kill and then whatever the process ID number is. Right. So for example, if you do kill space one, two, three, four, it targets processes, targets, it targets process with the ID number of one, two, three, four, and attempts to stop it safely. Now, for stop, sometimes it, you know, it you try to kill it and it won't it won't do anything, it still continue running. Then you have to force stop it. And that's the negative nine command. So it so in this example it would be kill space negative nine, one, two, three, four. The negative nine forces immediate termination. This is not clean, this does not save the data, it does not close gracefully. Should only use this force only when control has already been lost. Background versus foreground. Foreground runs in the active terminal, background runs behind the scenes. So, for example, processes with the and the and stamp, right? The and, right? A N D, right? Remember the symbol and so why does it matter? Because many system services run without user visibility. And it tells you what services are running. So, what's a service? A service is a background process that performs ongoing system tasks. For example, web servers, network managers, security services. System CTL or system control. It controls system services. For example, you want to do systemctl space start appache 2 or stop Apache 2, right? System CTL stop Apache 2 or System CTL status Apache 2. Why this matters? Because if a service fails, that system might appear normal or function incorrectly. So let's say the website the website is down. You don't guess why it's down, you check.

unknown 8:40

Right?

SPEAKER_01 8:41

So you will go system CTL space status space apache 2 and see what's the status. Result, the service is stopped. The fix, system CTL, space, start space Apache 2. Problem solved. Easy peasy.

unknown 8:58

Right?

Network Checks With Ping And Dig

SPEAKER_01 8:59

Package heart package manager. It's a system that installs, updates, and removes software. Why does it exist? Because Linux does not use random installers or download and click workflows, it uses trusted repositories. Common systems is apt, Debian based or DNF Yum for Red Hat based. So an example is you want to update your stuff, update, right? APT space update or APT install ng INX, right? For Debian based and for DNF and Yum, you write DNF space install space HTTPD. Why this matters? Because software is verified, managed, and controlled. Now we come back to something that we're familiar, right? The pin command. Right? The pin command tests connectivity between systems. It works exactly how the Windows pin command is, right? So for example, you want to ping Google, it's ping spacegoogle.com.

unknown 10:06

Right?

Cron And Invisible Automation

Why macOS Hides Complexity

Finder Dock Spotlight And Faster Work

SPEAKER_01 10:07

What does this tell you? That the network is reachable and then the path exists. Next we have the dig command and dig tests DNS resolution. So again, you know, you do dig.google.com. Right? What is the difference between ping and dig? Ping tests for connectivity, dig tests for name resolution. Next we have the etsy resolve or re s o v dot config. Config, yeah. C-o-n-f. Not config, conf, right? File that defines DNS servers used by the system. Why this matters? Because if DNS is wrong, internet works and the names fail. Automation, cron. Cron is a scheduler for automated tasks. Examples, crom tab minus E. What does it do? You can use it for backups, updates, scripts. Why does it matter? Because the real systems run tasks without human interaction. You don't need to be there 24-7, right? You can just set it up, especially now with AI. Set it up on what, and you don't have to be there. Now you understand that systems are not static, they are active environments. You know now that what processes are, how to monitor them, how to stop them, how the service operates, how software is installed, and how network is validated. And now we move to the final part. Right? How does the system hide complexity without removing control? Right? In Linux, everything's exposed. You type commands, you see structures, you control behavior directly. Mac OS takes a different approach. It asks, what if we kept the power but remove the friction? What macOS really is most people describe Mac as easy, clean, and user-friendly. All true, but incomplete. Mac OS is a Unix-based operating system designed to combine system level power with simplified user interface. The last part matters because Mac OS is not simpler, it is structured differently. Linux says you are responsible. Windows says we'll guide you. Mac says we'll simplify the experience, but the system still follows the rules, right? This is not a continuation of Linux, but this is just showing you the two main operating systems that other than Windows, because the the exam is like 90% Windows. The other two operating systems that could possibly be on the exam, though do not, like you don't need to be a Linux guru or a Mac guru. I mean, they're only gonna ask you maybe five questions total on both exams, I would think, on Linux and Mac. It's not, you know, it's Windows-centric, this exam. It's supposed to be vendor neutral, but it's really Windows-centric because mostly everybody has Windows. Right? 90 80, it's like 85% of the world uses Windows. So this is this is what the exam is based off. All right. Let's start with the Finder. Finder is the file management interface used to navigate and organize files in Mac OS. Why does it exist? Because not every user needs command line precision or system level visibility. Instead, they need clear visual access to their files.

unknown 13:55

Right?

SPEAKER_01 13:56

So instead of CD users, you know, Juan documents, and then type LS to see the list, you click for Finder, open documents, and then view files instantly. The system didn't change the interaction layer did. Right? The doc. The doc is a shortcut bar that provides quick access to frequently used applications. Why does it matter? Because macOS separates navigation or finder from access, which is the doc. The results, users don't search for apps, they launch instantly. Next is Spotlight. Spotlight is a system-wide search tool that allows users to quickly locate files, applications, and system functions. The shortcut is command plus space. That's the shortcut for that. Why this changes? Because instead of navigating folders or clicking menus, you ask the system directly.

unknown 14:55

Right?

macOS Unix Foundation And File Layout

SPEAKER_01 14:56

You could type terminal, press enter, and then system opens terminal instantly. Right? That's the example. Insight search replaces navigation, and speed replaces structure. Under the surface, Mac is still Unix, and so is Linux, right? It's a father, right? Unix is the father, and Linux and Mac are the are the sons. Here's what most users don't realize macOS is built on Unix, right? What that why does that matter? Underneath, it has the same file system concept, the same permission models, and the same command line tools. If you open terminal in Mac and you type LS, PW, and CD, they're the same command as Linux. Mac OS didn't remove complexity, it hid it until you need it.

unknown 15:49

Right?

FileVault Keychain Time Machine Basics

Force Quit And Activity Monitor

Practice Questions And Final Takeaways

SPEAKER_01 15:50

Bet you didn't know that LS, PW, and C D work in Mac, like in Linux. Our file system structure, Mac OS uses structure directories. You have your application directory with installed apps, system, which is your OS files, library is where shared resources are, and the users is the user data. Why does this matter? Because when troubleshooting, you must know where things live with beneath the surface. Next, we have the security that they have available in the Mac OS, protection without constant user input. You have your file volt, full disk encryption for Mac OS, kind of like BitLocker, right? Why does it exist to protect data if the data is lost or if it's stolen? Real world impact, without file volt, data can be extracted physically, and with it, it data remains encrypted. Keychain, which is your password management, is a secure storage system for passwords and credentials. Why does this matter? Because users reuse passwords and forget credentials. This is something that Windows does not have, which I imagine in the next version of Windows they will. Because not for nothing, guys, this thing with the passwords has gotten out of hand. Changing the password every 60 days now, and having 16 characters, you know, this is like the minimum that the government wants. I mean, we still in the corporate like 90, 90 days, I think 12 characters, but it's gonna go that way pretty soon. Um, you watch the government is off in the lead, and then the corporations follow later on. But yeah, it's it's it's a hassle, these passwords. Uh so you know, they reuse the passwords, they forget the credentials. So solution the macOS stores and protects them securely. Backup Time Machine. Time machine is an automated backup system that allows users to restore previous versions of files. Why is this powerful? Because it changes how recovery works. Real world scenario, user deletes a file instead of panic and rebuilding it, they open time machine, go back in time and restore files. Lesson backup removes fear. I don't I'm I'm not a big Mac user, so I don't, you know, I know Windows have the system restore, but the system restore does not restore the file if you did it, if you deleted it. It'll restore the app, I think, if you deleted it. But if it's the file, I think it's gone. So troubleshooting in Mac OS, even though Mac OS simplifies things, problems still exist. Force quit, right? You have the force quit command, it's command plus option plus escape. It terminates unresponsive applications, right? It's like control, alt-delete in Windows, and then you go in there and you end task, right? To terminate unresponsive applications. Why does it matter? Because sometimes processes don't respond to normal control. Activity monitor, it displays running processes and system performance, right? Equivalent to top or task manager, it looks like. So now you have structure, control, behavior, and interface. So let's test your thinking. And it's time for the Camtia style questions. As you know, I give you four questions. I'm gonna read it, give you the four choices, then read it again, give you five seconds, think about it, and then I'll tell you the answer. Question number one What is the primary function of the Linux shell? A manage hardware, B provide graphical interface, C, interpret and execute commands or D store files. What is the primary function of the Linux shell? A manage hardware, B provide graphical interface, C interpret and execute commands or D store files. Give you five seconds. Think about it. Five, four, three, two, one. The answer is C. The shell acts as the interpreter between the user and the operating system. It takes command, processes them, and executes system level actions. Question two. Which command provides real-time monitoring of system processes? A PS B L S C Top D C D. Which command provides real-time monitoring of system processes? A PS B L S C top or D C D? Give me five seconds to think about it. 5, 4, 3, 2, 1. The answer is C top. It continuously updates system activity showing CPU and memory uses dynamically, unlike PS, which provides a static snapshot. Question number three. What is the purpose of sudo in Linux? A delete files, B. Switch directories. C Run with elevated privileges or D restart system. What is the purpose of sudo in Linux? SUDO in Linux? A. Delete files. B switch directories. C Run commands with elevated privileges or D restart system. I'll give you five seconds. Think about it. 5, 4, 3, 2, 1. And the answer is C. Sudo allows users to execute specific commands with administrative privileges without fully switching to the root user. Right? Should be should be done temporarily, right? Last question. Hopefully you are three for three so far. And let's do like Wendy's and go four for four. That is so corny. Anyway, what is the primary role of the time machine in macOS? A. Install apps. B monitor system performance. C backup or restore files or D manage permissions. What is the primary role of time management in macOS? A install apps. B monitor system performance. C backup and restore files or D manage permissions. Give you five seconds to think about it. 5, 4, 3, 2, 1. The correct answer is C. Time Machine. Is Time Machine does backup and restore files? C, right? Backup and restore files. Time machine provides automated backups and allow users to recover files from previous dates. So if you made it through the entire two episodes that I've done, you've already done something most people don't. You didn't just learn commands, you learned how systems are structured, how access is controlled, how behavior is monitored, and how different interfaces present the same reality. And that's the difference. Anyone can memorize LS, CH mod, or Top, but technicians understand why those commands exist. Because in the real world, you won't always know the system, but you will understand the principles. And you will always find the answers. Alright, this has been Technology Tap. I'm Professor J. Ron. Stay sharp, stay curious, and as always, keep tapping into technology. This has been a presentation of Little Cha Chop Productions, art by Sarah, music by Joe Kim. We are now part of the Pod Match Network. You can follow me at TikTok at Professor J Rod at JROD. Or you can email me at Professor J Rod, J R O D at Gmail dot com.