 Hi students, in this video we will see what a shallow terminal is and also have a look at some of the very basic Linux commands. So right now what you are seeing is the Ubuntu 18 window, Ubuntu 18 is a Linux distribution. Let's open a terminal. I will increase the font size a bit. Okay. So what is a terminal? Terminal is just a process running on the CPU which allows us to type in various commands and based on what we enter it will execute certain actions and it will show me the corresponding output. So there is a set of predefined commands and what happens if I type in something which is not a command? It will say command not found. So now I will go through some of the very basic commands starting with PWD. PWD stands for Print Working Directory and it gives me the absolute path of my current directory. So I am currently at home slash sorob. Now that I know which directory I am in, I want to know what all are the files or folders which are inside this directory. So I can use the ls command. It shows me all the files and other folders inside this. There are certain hidden files which start with the dot and it is not showing me those as of now. I can use the hyphen argument which will show me all the hidden files along with other files and folders. So let's say if I want to create a new folder, I can use MKDIR command. So I will create a new folder called folder1 and if you do ls, so you can see that there is a new folder called folder1. So how can I get inside folder1? I can use cd command to change the directory. So I will type cd space folder1 and now you can see that the present directory is home slash sorob slash folder1. If I do ls, you can see that there is no file inside this folder. Let's create a new file. You can create a new file using touch command. So I will write touch new dot txt and let's see. So now you can see that there is a new file called new dot txt. I will create another folder inside this. So now if I want to move this new file to folder2, how can I do that? I can use the mv command. So I will type mv then the source path which is new dot txt and the destination path. So the destination is folder2. So here if you see we don't have new file inside folder1 and if we go to folder2 and do ls, so here it is. And how can we move it back to parent directory? So there is a special directory called dot dot which points to the parent directory. If I go back to the parent directory, I will use cd space dot dot and it will take me back to the parent directory. Now let's go inside folder2 again and now I want to move this new file back to folder1. So I can use mv new dot txt and dot dot. So it will move this new dot txt file to the parent directory. So it's not here and if you go back to the parent, so new dot txt is back in folder1. So what if I want to copy this new file to folder2 so that it's both in folder1 and folder2. So I can use cp new dot txt folder2. So cp is the source path and the destination path. So now if you do ls, so we have a new file here and inside folder2 also we have the new file. So how can we delete a file? I can use the rm command. If I press rm space new dot txt, so now if I do ls, you can see that file is not here. So I have deleted this new file. Let's go to the parent directory and let's try to remove folder2 using the same rm command. So it says it cannot remove because it is a directory. So we can use rmdir command which is used to remove a directory. So now if you do ls, it has removed folder2. But rmdir can only be used when a folder is empty. So if I go to the parent directory and try to remove folder1, it says fail to remove because directory is not empty. So how can we remove a directory along with its contents? We can use rm with r argument. So here r stands for recursive. So it will recursively delete everything which is inside folder1 and then it will delete folder1 itself. So now if I do ls, you can see that we don't have folder1 anymore. So now let's see another command which is used to install new packages which is the apt command. So if I want to install virtualbox, I can type apt install virtualbox. It says could not open log file permission denied and why does it say so? So if I want to install anything in my Ubuntu, I need root privilege. So if I want to run any command with root privilege, I can type in sudo space that command and it will run this command with root privilege. So it asks for my password, I will enter the password. If it has started installing, it says this much mbo of additional disk will be used. So I will exit the installation for now using ctrl plus c. Now whenever I come across any new command and I want to know what it does, I can use the man command which shows us the manual page of any command. So if I type man space pwd, it tells me that it prints the full file name of the current working directory. I can exit this using q. And let's see the man page of ls command, it says that it lists information about the files and if you remember we had used this a argument and it says that it do not ignore entry starting with a dot. So it shows all the files including the hidden files. Okay, so let's exit this. In fact there is a man page for man command itself and it says they say an interface to the online reference manuals. You can go through these man page and learn about different arguments. Finally how can we exit the shell, you can use the exit command. So that's it for this video, thanks and have a nice day.