Hi, I'm Rob. I'm Candace. Congrats on making it through this course. Now that you've made it this far, we're here to give you a sneak peek into what an interview on the technical subjects covered by this course might look like. We hope this will help you have a better idea of what to expect in your next interview. Just remember to keep learning and keep practicing. All right. So for this scenario, let's say that you stopped by to see a user at their desk and they reported some kind of application issue. When you get there, they show you the problem. They're trying to launch an application from a shortcut on their desktop and every time they double-click on it, they get this generic error message that says, "There was an error launching the application." Start troubleshooting that for me. What OS are you using and what's the name of the application? Say it's Linux desktop and it's a custom application. We'll say that I built it in-house. Let's call it Application X. Okay. Do you remember the last time this worked? Sure. We can say it worked on Friday and today is Monday. Okay. Do you know if there's any other users that's having this issue? So this is the first report of it but it's still early on a Monday. Okay. Are you aware if there is any type of updates that happened over the weekend? Not that I'm aware but is there any way we can check? So we can check the Apt log. What is Apt? Apt is pretty much a utility that we use in installing applications and updates. Great. Cool. So where were we? Can you walk me through where we can find the logs for Apt? I'm actually not sure where the logs for the application would be at. Great, and how might you find it out if this was a real-world scenario? We can probably check the main page or search online. Okay. Great, that's a good idea. So, let's say that you're able to find out that the log is in slash var, slash log, slash apt, and the file that we're looking for is history.log. Now that you've got that file, we've got a hundred different entries in here. How do we find what we're looking for specifically just for this application? We can use the grep command with the application name. Okay. Let's say we do that and we find that there was an update done just over this past weekend. So it's actually possible that the update could have caused this issue. There could be a missing dependency or the application could have gotten corrupted. So we can also check permissions, too. So where do we start? So I want you to run a few updates just to make sure everything's installed and there's no missing dependencies. So first, I want you to run sudo apt get update and then sudo apt get upgrade. Okay. Great. So let's say that those both run, they complete successfully, what do we do now? So let's try and launch the application. So it still fails, same exact error. So I think now, we should probably check the permissions. All right. How do we do that? So first, you want to get the location. So we can probably get the location by right clicking on the shortcut and then seeing what the command section says. Okay. So we do that and let's say it says application dash x as the command. So now, you want to use the which command with the location that provide it. Okay. We'll say it's located in slash usr, slash bin. So now, you want to navigate with cd to the directory of that application. Okay. Say we're there. Okay. So now, you want to list out all the permissions. So you want to do ls space hyphen L? Okay, so here's what I see. Dash RWX, R dash X, dash dash dash, then it says root, space, root. Can you explain to me what this all means? R stands for read, W stands here write, X stands for execute. The first [inaudible] three is associated with the owners of the application, the second set of three is associated with the groups of the application, and then the last set of three is associated for other or users. Root is associated with the owner and then the second root is associated with the group. Okay. So after looking at all that, does anything stand out as wrong here? Yes. So since the last [inaudible] three is associated with users and other, I'm noticing that there's no read or execute permissions for this application. Okay. How do we correct that? So we can use a change modify command, ch mod, to update the permissions. Okay. So now it's fixed for me, we tried the application, everything works. Any follow up that we need to do? Yes. I would want to notify the owners of the application because it's going to affect a lot of users and this will also help prevent reoccurring issues from happening. Okay. Good. Thank you. In this scenario, we saw a lot of back and forth which is very common for troubleshooting interviews. The initial description was very broad and the candidate used several follow-up questions to better scope the problem. Since the error message wasn't clear, there were several possible causes of the problem. Eliminating the most likely culprits first allowed us to keep trying until we found the actual cause. We also showed that it's okay if you don't know everything. The candidate didn't know where the log for apt is stored but she explained how she would find that out if this were a real-life issue she we're trying to address. When you do that, it shows that you're resourceful and a good problem solver. It's impossible to know everything but knowing where to find answers is a critical skill for an IT support specialist. That's it for now. See you again at the end of our next course.