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Assignment No.-
BASIC LINUX COMMANDS
Aim: Demonstration of basic Linux Commands and Understanding the working of Linux Operating System
Objectives:
- To understand the basics of Linux Operating System
- To execute basic Linux commands.
Theory:
Linux is an operating system's kernel. You might have heard of UNIX. Well, Linux is a UNIX clone. But it was actually created by Linus Torvalds from Scratch. Linux is free and open-source, that means that you can simply change anything in Linux and redistribute it in your own name! There are several Linux Distributions, commonly called “distros”.
- Ubuntu Linux
- Red Hat Enterprise Linux
- Linux Mint
- Debian
- Fedora
Linux is Mainly used in servers. About 90% of the internet is powered by Linux servers. This is because Linux is fast, secure, and free! The main problem of using Windows servers are their cost. This is solved by using Linux servers. The OS that runs in about 80% of the smartphones in the world, Android, is also made from the Linux kernel. Most of the viruses in the world run on Windows, but not on Linux! Linux Shell or “Terminal”
So, basically, a shell is a program that receives commands from the user and gives it to the OS to process, and it shows the output. Linux's shell is its main part. Its distros come in GUI (graphical user interface), but basically, Linux has a CLI (command line interface). In this tutorial, we are going to cover the basic commands that we use in the shell of Linux. To open the terminal, press Ctrl+Alt+T in Ubuntu.
Linux Commands
1. pwd — When you first open the terminal, you are in the home directory of your user. To know which directory you are in, you can use the “pwd” command. It gives us the absolute path, which means the path that starts from the root. The root is the base of the Linux file system. It is denoted by a forward slash( / ). The user directory is usually something like "/home/username". 2. ls — Use the "ls" command to know what files are in the directory you are in. You can see all the hidden files by using the command “ls -a”. 3. cd — Use the "cd" command to go to a directory. For example, if you are in the home folder, and you want to go to the downloads folder, then you can type in “cd Downloads”. Remember, this command is case sensitive, and you have to type in the name of the folder exactly as it is. But there is a problem with these commands. Imagine you have a folder named “Raspberry Pi”. In this case, when you type in “cd Raspberry Pi” , the shell will take the second argument of the command as a different one, so you will get an error saying that the directory does not exist. Here, you can use a backward slash. That is, you can use “cd Raspberry\ Pi” in this case. Spaces are denoted like this: If you just type “cd” and press enter, it takes you to the home directory. To go back from a folder to the folder before that, you can type “ cd ..”. The two dots represent back. 4. mkdir & rmdir — Use the mkdir command when you need to create a folder or a directory. For example, if you want to make a directory called “DIY”, then you can type “mkdir DIY ”. Remember, as told before, if you want to create a directory named “DIY Hacking”, then you can type “mkdir DIY
Hacking ”. Use rmdir to delete a directory. But rmdir can only be used to delete an empty directory. To delete a directory containing files, use rm.
8. cp — Use the cp command to copy files through the command line. It takes two arguments: The first is the location of the file to be copied, the second is where to copy. 9. mv — Use the mv command to move files through the command line. We can also use the mv command to rename a file. For example, if we want to rename the file “ text ” to “ new ”, we can use “ mv text new ”. It takes the two arguments, just like the cp command. 10. locate — The locate command is used to locate a file in a Linux system, just like the search command in Windows. This command is useful when you don't know where a file is saved or the actual
name of the file. Using the -i argument with the command helps to ignore the case (it doesn't matter if it is uppercase or lowercase). So, if you want a file that has the word “hello”, it gives the list of all the files in your Linux system containing the word "hello" when you type in “ locate -i hello ”. If you remember two words, you can separate them using an asterisk (*). For example, to locate a file containing the words "hello" and "this", you can use the command “ locate -i hellothis”.
Intermediate Commands
1. echo — The " echo " command helps us move some data, usually text into a file. For example, if you want to create a new text file or add to an already made text file, you just need to type in, “ echo hello, my name is alok >> new.txt ”. You do not need to separate the spaces by using the backward slash here, because we put in two triangular brackets when we finish what we need to write. 2. cat — Use the cat command to display the contents of a file. It is usually used to easily view programs. 3. vi —vi is already installed text editors in the Linux command line. You can create a new file or modify a file using this editor. For example, if you need to make a new file named "check.txt ", you can create it by using the command “ vi check.txt ”. You can save your files after editing by using the sequence Ctrl+X, then Y (or N for no).
Conclusion:
Thus, we have understood the working of Linux operating system and executed Linux commands successfully and observed the output.
