In Linux, the main directory that all other stem from is called the root directory. The path to the root directory is denoted by a slash or forward slash. An example of a path in Linux that starts from the root directory is /home/cindy/Desktop. Just like c:\users\cindy\desktop in Windows. Let's go ahead and see what's under the root directory. We're going to be using the ls or list directory contents command. We also want to give this command, the path, the directory that we want to see. If we don't provide a path, it will just default to the current directory we're in. So ls slash. All right, now we can see all the directories that are listed under the root directory. There are a lot of directories here, and they're all used for different purposes. We won't go through them all, but let's talk about a few of the important ones. Slash bin, this directory stores our essential binaries or programs. The ls command that we just used is a program, and it's located here in the slash bin folder. It's very similar to our Windows program files directory. Slash etc, this folder stores some pretty important system configuration files. Slash home, this is the personal directory for users. It holds user documents, pictures, and etc. It's also similar to our Windows users directory. Slash proc, this directory contains information about currently running processes. We'll talk more about processes in an upcoming lesson. Slash user, the user directory doesn't actually contain our user files like our home directory. It's meant for user installed software. Slash var, we store our system logs and basically any file that constantly changes in here. The ls command has a couple of very useful flags that we can use too. Similar to Windows command parameters, a flag is a way to specify additional options for a command. We can usually specify a flag by using a hyphen then the flag option. This varies depending on the program, though. Every command has different flag options. You can actually view what options are available for a command by adding the dash, dash help flag. Let's see this in action. There's an incoming wall of text, but don't panic. You don't have to memorize these options. This is mainly used for reference. For now, let's just quickly go through the help menu At the top here it tells you what format to put the command in. And here it gives you a description of what the command does. This huge chunk of text lists the options that we can use. It tells us what command flags are available and what they do. The dash, dash help flag is super useful, and even experienced OS users refer to it every so often. Another method that you can use to get information about commands is the man command from manual. It's used to show us manual pages, in Linux we call them man pages. To use this command, just run man, then the command you want to look up. So let's look up man ls. And here we get the same information as dash, dash help, but with a little more detail. Okay, back to using the ls command. Right now, it's not quite friendly to read. So let's make our directory list more readable with the dash l flag for long. This shows detailed information about files and folders in the format of a long list. Now we can see additional information about our directory and the files and folders in them. Similar to the Windows show properties, the ls command will show us the detailed file information. Let's break down this output starting from the left. The first column here are file permissions, side note, we're going to cover file permissions in an upcoming lesson. Okay, next up is the number of links a file has. Again, we'll discuss this is more detail in a later lesson. Next, we have the file owner, then the group the file belongs to. Groups are another way we can specify access, we'll talk about this in another lesson too. So then we have the file size. The time stamp of last modification, and finally, the file or directory name. The last slide that we'll discuss for the ls command is the dash a or all option. This shows us all the files in the directory including the hidden files. You'll notice that I appended two different flags together. This is the same thing as ls -l -a /. Both work the exact same way. The order of the flag determines which order it goes in. In our case, it doesn't matter if we do a long list first or show all files first. Check out how there are some new files are visible when we use these flag. The dash a or all flag, shows all files including hidden ones. You can hide a file or directory by pre-pending a dot to it. Like the file shown here .I_am_hidden. We've covered a lot in this video, we've learned how to view detailed information about files with the ls command. We also started using computer paths and we learned how to get help with commands using the dash dash help flag and man pages. We even took a sneak peek at our Linux files system. If I went through any of this a little too quickly, just rewatch the video. We'll meet back up in the next one, where we'll start changing directories in the GUI. See you there.
