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<v Speaker 1>You know, when you pick up a technical manual, you

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<v Speaker 1>usually expect the dedication page to be standard boilerplate, like

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<v Speaker 1>to my spouse or to my kids. It's sweet, but

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<v Speaker 1>it's completely predictable.

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<v Speaker 2>It's the one page of the text you generally just

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<v Speaker 2>flip right past to get to the actual architecture diagrams

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<v Speaker 2>right exactly.

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<v Speaker 1>But today we are doing a deep dive into Ahmed

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<v Speaker 1>al Khaberi's work. Learn Linux Quickly, and his dedication genuinely

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<v Speaker 1>made me laugh out loud. He thanks his mom naturally,

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<v Speaker 1>but then he drops this note to his dad. He says,

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<v Speaker 1>I know you wanted me to go to medical school

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<v Speaker 1>to be a doctor, just like you. Sorry, pops, computer

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<v Speaker 1>science is the future.

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<v Speaker 2>I mean, it is a very confident opening m but

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<v Speaker 2>historically speaking, he really wasn't wrong to make that bet.

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<v Speaker 1>He was completely right. And that is our mission for

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<v Speaker 1>you today to decode the architecture of the world's most powerful,

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<v Speaker 1>yet largely invisible operating system, Linux, because if your perception

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<v Speaker 1>of Linux is still stuck on that old trope of

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<v Speaker 1>a lone hacker in a dark room compiling source code,

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<v Speaker 1>you're missing the macro scale of what this system actually is.

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<v Speaker 2>Oh, absolutely. The scale is staggering when you actually look

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<v Speaker 2>at the numbers.

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<v Speaker 1>Right, we are talking about the engine powering over ninety

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<v Speaker 1>percent of the world's supercomputers, seventy five percent of all

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<v Speaker 1>cloud solutions, your Android phone, government servers, Lexus and Toyota

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<v Speaker 1>smart cars, and I mean even some washing machines.

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<v Speaker 2>Yeah, you are interacting with a Linux kernel dozens of

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<v Speaker 2>times a day, even if a command line interface never

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<v Speaker 2>once flashes across your screen.

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<v Speaker 1>It's wild. Okay, let's unpack this before we start parsing

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<v Speaker 1>command syntax and all that. We need to understand where

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<v Speaker 1>it came from, because we need to know how it

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<v Speaker 1>differs from the systems we're used to, like Windows or macOS.

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<v Speaker 2>Well, the contrast with proprietary systems is stark, unlike Windlows

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<v Speaker 2>or mac which were engineered by massively funded corporate teams

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<v Speaker 2>under strict NDAs. Linux originated in nineteen ninety one as

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<v Speaker 2>a mere hobby project. Wait, a hobby project, yeah, by

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<v Speaker 2>Linus Torvoldz who just a computer science student in Fenmlas

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<v Speaker 2>and at the time he built his own Unix like

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<v Speaker 2>operating system and crucially it became the ultimate open source.

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<v Speaker 1>Project, meaning the source code, like the actual underlying logic

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<v Speaker 1>of the software is entirely public. Anyone can edit it.

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<v Speaker 1>But let me push back on this for a second.

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<v Speaker 2>Sure, go ahead. Wait.

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<v Speaker 1>If it's free and literally anyone on the internet can

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<v Speaker 1>edit it, how is it secure and stable enough to

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<v Speaker 1>run massive corporate infrastructure for like Amazon or Google?

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<v Speaker 2>That is a totally fair question. The open source model

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<v Speaker 2>relies on the idea of thousands of developers constantly reviewing

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<v Speaker 2>and patching the code. But to really understand how it

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<v Speaker 2>maintains stability for an Amazon server farm, we have to

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<v Speaker 2>break down the anatomy of the system. We have to

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<v Speaker 2>separate the concept of the operating system from the kernel.

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<v Speaker 1>Right, let's draw that line. Because people use those terms interchangeably,

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<v Speaker 1>don't they all the time?

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<v Speaker 2>But they are very different. The operating system is the

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<v Speaker 2>complete package. It includes the graphical user interface, text editors,

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<v Speaker 2>all the bundled apps. It manages the hardware and software overall,

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<v Speaker 2>but the kernel. What's fascinating here is that the kernel

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<v Speaker 2>is strictly the core.

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<v Speaker 1>The absolute center of it all exactly.

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<v Speaker 2>It's the part that organizes access to the CPU memory

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<v Speaker 2>and disc doesn't care about your web browser. It just

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<v Speaker 2>dictates resource allocation.

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<v Speaker 1>Let me try to map this out with an analogy

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<v Speaker 1>to see his tracks. So the operating system is a

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<v Speaker 1>full restaurant. You have the tables, the menus, the waiters,

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<v Speaker 1>the whole dining room. That's the environment we interact with.

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<v Speaker 2>I like where this is.

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<v Speaker 1>Going, But the kernel is the busy kitchen expediter. They

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<v Speaker 1>aren't talking to the customers at all. They actually decide

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<v Speaker 1>which chef gets which ingredients, which pan goes on which burner,

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<v Speaker 1>and exactly when a dish gets plaited.

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<v Speaker 2>That analogy holds up perfectly. And because this expeditor the

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<v Speaker 2>Linux kernel is open source, developers quickly realized they didn't

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<v Speaker 2>have to build just one type of restaurant around.

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<v Speaker 1>It, right, They could build thousands of different types of

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<v Speaker 1>dining rooms, all using that same amazing expeditor in the

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<v Speaker 1>kitchen exactly.

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<v Speaker 2>And that brings us to the concept of distributions or distros.

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<v Speaker 2>Since the kernel is free, people package it with different

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<v Speaker 2>apps and interfaces to create unique variations. Android is actually

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<v Speaker 2>a Linux distro.

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<v Speaker 1>Oh wow, I didn't even realize Android counted as a distro,

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<v Speaker 1>And Alcaberi mentions one called scientific Linux.

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<v Speaker 2>Right, yes, scientists use Scientific Linux specifically because it comes

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<v Speaker 2>pre packed with specialized scientific apps and research tools.

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<v Speaker 1>There are distros for everything, so if you're listening to

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<v Speaker 1>this and want to try it out, replacing your Windows

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<v Speaker 1>OS with a Linux distro sounds honestly terrifying for a beginner,

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<v Speaker 1>but the book has a safe way to play around.

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<v Speaker 2>Right, very safe. The book strongly suggests using a virtual

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<v Speaker 2>machine or a VM. You definitely don't need to wipe

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<v Speaker 2>your hard drive.

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<v Speaker 1>Which is a relief. A VM is basically like the

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<v Speaker 1>movie Inception for computers. It's a dream within a dream.

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<v Speaker 2>Ah, that's exactly what it is.

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<v Speaker 1>It's a computer running inside your host computer. It shares

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<v Speaker 1>your physical resources, but acts as a completely standale, isolated machine.

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<v Speaker 2>Right, so if you completely break the Linux system while learning,

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<v Speaker 2>you just delete the VM and start over. Your actual

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<v Speaker 2>computer is totally fine.

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<v Speaker 1>The technical specifics in the book are great for this.

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<v Speaker 1>You use a program called virtual box, grabbing a Buntu

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<v Speaker 1>ISO image and set it up. Alceberry suggests giving it

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<v Speaker 1>at least two gigabytes or ideally four gigabytes of RAM

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<v Speaker 1>and a dynamically allocated hard disc of at least ten gigabytes.

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<v Speaker 2>Four gigs of Ram is really the sweet bot if

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<v Speaker 2>you want the graphical interface of a Buntu to run

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<v Speaker 2>smoothly without lagging your host machine.

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<v Speaker 1>And there's this fun pop culture easter egg in the book.

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<v Speaker 1>When you create your username during setup, the author suggests

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<v Speaker 1>using Elliott.

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<v Speaker 2>A nod to the TV show Mister Robot.

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<v Speaker 1>Yep, the hacker main character. It's a great touch. So

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<v Speaker 1>you've booted up your Ubuntu virtual machine. You see a

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<v Speaker 1>familiar graphical user interface or GUI. You have apps like Libra,

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<v Speaker 1>Office and Dash. But to be a true power user,

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<v Speaker 1>you have to leave the mouse behind.

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<v Speaker 2>You really do. The guy is nice, but the real

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<v Speaker 2>of Linux is in the command line.

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<v Speaker 1>And this brings up a major point of confusion for beginners,

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<v Speaker 1>the difference between the terminal and the shell.

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<v Speaker 2>Oh, people mix these up constantly.

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<v Speaker 1>Let's go back to the drive through for an analogy.

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<v Speaker 1>The terminal is just the drive through speaker box. It's

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<v Speaker 1>the physical or emulated window where you speak your order.

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<v Speaker 2>Right. The terminal just displays the text. It doesn't actually

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<v Speaker 2>understand what you're typing exactly.

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<v Speaker 1>But the shell is the line cook wearing the headset

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<v Speaker 1>inside the shell is interpreting your order and actually making

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<v Speaker 1>the food or you know, executing the commands.

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<v Speaker 2>This raises an important question, though, what happens when you

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<v Speaker 2>type absolute gibberish into the terminal like you just mash

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<v Speaker 2>your keyboard and hit enter.

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<v Speaker 1>It doesn't crash, No, not at all.

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<v Speaker 2>The shell simply replies command not found. It's a literal interpreter.

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<v Speaker 2>If it doesn't recognize the exact order, it just hands

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<v Speaker 2>it back to you.

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<v Speaker 1>Here's where it gets really interesting to me. I love

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<v Speaker 1>how literal Linux commands are. You don't need to memorize

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<v Speaker 1>arcane magic spells. The commands are exactly what they do.

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<v Speaker 2>The Unix philosophy is to do one thing and do

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<v Speaker 2>it well, so the commands are very straightforward.

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<v Speaker 1>Let's run through some examples. You type date and it

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<v Speaker 1>prints the system date and time simple enough. You type

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<v Speaker 1>Michael Fagele it prints the calendar, and I love this.

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<v Speaker 1>You can time travel. You can type I'll call twenty

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<v Speaker 1>twenty two to see that year, or even autocoll FEP

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<v Speaker 1>nineteen ninety three.

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<v Speaker 2>Surprisingly fun, just to see what day of the week

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<v Speaker 2>you were born on. Yeah.

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<v Speaker 1>Then there's clear, which just wipes the screen when it

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<v Speaker 1>gets too messy, an echo, which literally repeats back whatever

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<v Speaker 1>you type. So if you type echo, cats are better

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<v Speaker 1>than dogs, it just prints cats are better than dogs.

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<v Speaker 2>Right back, which seems silly at first, but echo is

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<v Speaker 2>actually vital later on for writing automated scripts makes sense.

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<v Speaker 1>And my absolute favorite history. It shows a number list

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<v Speaker 1>of everything you've typed. If you want to run the

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<v Speaker 1>seventh command you typed again, you don't retype it. You

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<v Speaker 1>just type an exclamation point in the seventh like point seven.

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<v Speaker 2>It saves so much time. But commands rarely just run

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<v Speaker 2>in their basic state. They have options or flags to

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<v Speaker 2>change the behavior.

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<v Speaker 1>Right. Let's talk about hyphens, because this confused me at first.

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<v Speaker 2>Sure, a single hyphen is for abbreviations like a single letter,

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<v Speaker 2>so H. A double hyphen is for full words so human.

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<v Speaker 1>So if I want to check my available memory, I

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<v Speaker 1>type free, but it gives me the answer in raw kilobytes,

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<v Speaker 1>which is practically unreadable for a normal person.

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<v Speaker 2>Right, It's just a massive string of numbers.

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<v Speaker 1>So you add the option. You can type free H

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<v Speaker 1>or free human, and they do the exact same thing.

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<v Speaker 1>They display the memory in megabytes or gigabytes, a format

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<v Speaker 1>humans can actually read exactly.

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<v Speaker 2>Options just modify the command's default behavior. Now, we know

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<v Speaker 2>how to ask the computer for the date or its memory,

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<v Speaker 2>but how do we ask it how hard it's working

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<v Speaker 2>right now?

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<v Speaker 1>Taking the system's pulse, that is where the uptime command

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<v Speaker 1>comes in. You type it and it shows how long

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<v Speaker 1>the system has been running, who is logged in, and

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<v Speaker 1>something kind of intimidating called load average.

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<v Speaker 2>Load average is a great metric, but it confuses a

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<v Speaker 2>lot of people. It outputs three decimal numbers.

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<v Speaker 1>Yeah, what exactly do those three numbers mean?

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<v Speaker 2>They represent the system load basically the amount of work

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<v Speaker 2>the CPU is doing over the past one minute, five minutes,

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<v Speaker 2>and fifteen minutes.

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<v Speaker 1>So if my system is doing absolutely nothing, what does

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<v Speaker 1>it say?

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<v Speaker 2>A load average of zero point zero means the system

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<v Speaker 2>is completely idle. No processes are waiting in line for

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<v Speaker 2>the CPU.

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<v Speaker 1>Okay, so why does it give me three different timeframes, one, five,

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<v Speaker 1>and fifteen.

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<v Speaker 2>Because spotting trends is critical. Let's say your numbers are

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<v Speaker 2>two point zero zero four point zero zero zero zero.

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<v Speaker 2>The one minute load is a two, but the fifteen

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<v Speaker 2>minute load is a six. That means the system load

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<v Speaker 2>is much lower now than it was fifteen minutes ago.

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<v Speaker 1>Ah, so the system is cooling down exactly.

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<v Speaker 2>But if the numbers are reversed like five point zero zero,

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<v Speaker 2>three point zero two point zero zero, your one minute

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<v Speaker 2>load is way higher. That means the system load is

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<v Speaker 2>actively spiking right now.

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<v Speaker 1>That's incredibly useful for diagnosing a slow server. And Alcaberi

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<v Speaker 1>also notes you can use the lcpu command to quickly

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<v Speaker 1>list your CPU architecture and DFAIH to check available disk

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<v Speaker 1>space right.

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<v Speaker 2>Df stands for disc free, and throwing that H on

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<v Speaker 2>there makes it human readable again.

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<v Speaker 1>So now we know how the system is feeling and

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<v Speaker 1>how hard it's working, but we need to know how

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<v Speaker 1>to move around inside its brain. Where are all these

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<v Speaker 1>files actually.

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<v Speaker 2>Kept the filesystem? This is where Linux is very different

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<v Speaker 2>from Windows, which uses C drives and D drives.

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<v Speaker 1>Yeah. Algebra explains that the Linux filesystem is like an

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<v Speaker 1>upside down tree. It starts at the very top with

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<v Speaker 1>the root directory, which is represented simply by a single

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<v Speaker 1>forward slash.

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<v Speaker 2>Just everything branches out from that single forward slash, and.

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<v Speaker 1>To move around you use CD, which stands for change directory.

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<v Speaker 1>So CD takes you to the very top, but if

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<v Speaker 1>you get lost, use PWD.

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<v Speaker 2>Right working directory.

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<v Speaker 1>Yes, I love PWD, it's the ultimate you are here

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<v Speaker 1>a red star on a mall map. If you're lost,

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<v Speaker 1>you just have PbD and it tells you exactly what

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<v Speaker 1>folder you're standing in.

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<v Speaker 2>It's essential, and once you know where you are, you

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<v Speaker 2>use LS to list the files, or ll ls l

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<v Speaker 2>e L for a long list that shows all the

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<v Speaker 2>file permissions.

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<v Speaker 1>The directory structure is so organized too. It's not just

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<v Speaker 1>a free for all.

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<v Speaker 2>Oh, it is trickly segregated by design. For example, you're

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<v Speaker 2>the home directory, which is where regular users live, your documents,

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<v Speaker 2>your downloads, but.

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<v Speaker 1>The administrator, the root user, doesn't live there.

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<v Speaker 2>No, the root user has their own exclusive home called Root.

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<v Speaker 2>It's completely separate from regular users to prevent accidental damage.

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<v Speaker 1>And then there's Bin and SPIN. Bin holds your essential

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<v Speaker 1>everyday programs, your standard binaries, but SPIN holds the system

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<v Speaker 1>administration programs.

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<v Speaker 2>Right, the tools that require special privileges to run. It

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<v Speaker 2>keeps the heavy machinery locked away from the standard tools.

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<v Speaker 1>But there is one directory that comes with a massive

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<v Speaker 1>warning label, the tempep directory.

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<v Speaker 2>Ah, yes, the temporary folder.

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<v Speaker 1>This holds temporary files obviously, but the book explicitly warns

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<v Speaker 1>you never ever store important files here. Why is that?

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<v Speaker 2>Because of how it's mounted. In many systems, TEMP exists

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<v Speaker 2>in the system's volatile memory. Yeah, meaning the moment this

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<v Speaker 2>system reboots or loses power, that entire wi your folder

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<v Speaker 2>is wiped out completely, just poof gone exactly. It's designed

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<v Speaker 2>for apps to drop temporary session data and clean it

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<v Speaker 2>up automatically. If you save your novel on there and

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<v Speaker 2>restart your computer, it is gone forever.

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<v Speaker 1>That is a brutal lesson to learn the hard way.

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<v Speaker 1>So let's zoom out think about how far we've come

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<v Speaker 1>today on this deep dive.

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<v Speaker 2>Let's a lot of ground to cover.

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<v Speaker 1>We started with understanding Linus Torvald's little nineteen ninety one

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<v Speaker 1>hobby project. We talked about spinning up in a Buntu

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<v Speaker 1>virtual machine, literally talking directly to the shell with commands

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<v Speaker 1>like echo and corticle. We learned how to check the

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<v Speaker 1>CPU's load average to spot performance bikes, and navigated the

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<v Speaker 1>upside down tree of the root file system.

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<v Speaker 2>Once you understand the logic, it's actually incredibly elegant.

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<v Speaker 1>So what does this all mean? Why go through the

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<v Speaker 1>effort of learning to talk to a machine like this?

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<v Speaker 2>Well, I think it leaves you with something really fascinating

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<v Speaker 2>to ponder think about this. The very same free, open

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<v Speaker 2>source code written by a college student as a fun

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<v Speaker 2>hobby in nineteen ninety one is currently washing your clothes.

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<v Speaker 2>It's managing global banking clouds. It is literally running the

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<v Speaker 2>International Space Station right now.

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<v Speaker 1>That is insane to think about.

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<v Speaker 2>It really makes you wonder what other small, collaborative, weird

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<v Speaker 2>little hobbies happening on the Internet right now might quietly

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<v Speaker 2>become the invisible infrastructure of our future.

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<v Speaker 1>A hobby today, the invisible engine of the world tomorrow.

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<v Speaker 1>Thanks for taking this deep dive with us, and we'll

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<v Speaker 1>see you on the next one.