Welcome back to Linux Fundamentals. This is the first course in the Linux Foundation Specialization. In this module, we want to think about how to view, create, copy, move, and rename files. Basically, we're thinking about how to manage files and directories in the Linux operating system. Some learning objectives. When you're all done with this module, I want you to be able to view and create files, copy and move files, remove files, create links for files and directories, read portions of files, read complete files, and find differences in files. In this first lesson, we're going to think about handling files and directories. Some commands here, the ls command, I want to do a deep dive. We've looked at it a little bit before. But essentially the syntax looks like this. You say ls with the options followed by the path. The example in front of you in the console is ls minus a. Minus a says list all files including the hidden files, and hidden files start with a period. So you'll see in that directory the period docker environment is a hidden file in the current directory. The minus A option lists all files including hidden files except for the dot and double-dot files. These refer to the entries for the current directory and the parent directory. So here you'll see the dot and the double-dot right there. Then the minus R lists all files recursively descending down the directory tree from the given path. In my case, in the example, I don't give you a path which assumes the current directory, otherwise, you could tell it a specific path to work in. There's also a minus l option that lists the files in long format. This is with an index number, an owner name, a group name, a size, and permissions. There's a minus o option which lists the files in long format, but without the group name. There's a minus g, which is going to list the files in long format, but without the owner name. There's a minus i which lists the files along with their index number, and there's a minus s which lists the files along with their size. So there's lots of options. We're going to play around with them a little bit in a lab. There's a minus t which is going to sort the list by time of modification with the newest at the very top. There's a minus S which sorts the list by size with the largest at the top, and there's a minus r, which reverses the sorting order, so it makes the smallest at the top. Just a little bit of a review of some things we saw earlier. For file commands, we saw cat, which lists the contents of a file onto standard output. Later on in this course, we're going to talk about redirection so we can send it and create new files. We have the cp to copy files or directories. You see the example in front of you where I copy a file. We have the mv to move or rename files or directories. We have the make directory, which creates a new directory in the current directory, and we have the rm to remove files and directories. Lastly, the touch command, which updates the time and date of a file. A little review here. The touch command can create a new file. So if you touch something and it doesn't exist, it creates a file and puts a current date and time on it. The ls command can show hidden files with the right switches, and many commands work with both directories and files. I'll see you in the next lesson.
