Introductions to Linux Commands for Beginners

If you're new to Linux, or just never bothered to explore the command line, you may not understand why so many Linux enthusiasts are typing commands in the terminal with enthusiasm. could use a bunch of tools and apps to do it for them. Here are some of the command line wonders that could make you addicted to Terminal.

To use the command line, you must first launch a command tool, also called "command prompt". How you do this depends on the version of Linux you are using. 

For example, on RedHat, an "Activities" tab, visible at the top of the screen, allows you to open a list of options and a small window for entering an order ("cmd" will open the window). On Ubuntu and other systems, a small Terminal icon is visible on the left side of the screen. 

On many systems, pressing "Ctrl + Alt + t" allows you to open a command window. Finally, by connecting to a Linux system using a tool like PuTTY, you can access the Terminal directly.

Once in the command line window, the user is faced with a prompt either in the form of a simple "$" or something more elaborate like "user @ system: ~ $". In all cases, this means that the system is ready to execute your orders.

When we get to this point, we can start writing commands, but first you’ll need to get a Linux laptop for programming. Below are some commands to test first. To complete, you can easily find lists summarizing and explaining the most important Linux commands.

The main commands:

• PWD Indicates where we are in the file system (initially, this will be your original directory)
• ls Displays files in a directory
• ls -a Displays an even longer list of files (including those that start with a dot)
• ls -al Displays a list of all files with many details (including dates, file size, and permissions)
• who indicates who is online (don't be surprised if it's just you)
• date Recalls today's date (also indicates time)
• ps Displays running processes (can be reduced to shell and "ps" command )

Once you've gotten used to the Linux command line, there's nothing stopping you from expanding your explorations.

Commands like these can, for example, allow you to navigate the file system:

• cd / tmp Moves to another directory (in this case / tmp )

• ls Displays files there

• cd Returns to the user's directory (without argument, the cd command always brings you back to your directory)

• cat .bashrc Displays the contents of a file (in this case, .bashrc )

• history Displays recent order history

• echo "hello" Poster "hello"

• cal Displays the calendar for the current month

To understand even better why advanced Linux users love the command line so much, you'll probably want to test other features, like redirection and pipes. Redirection consists of taking the result of order and including it in a file instead of displaying it on the screen. Pipes are commands that send the result of one command to another command which will exploit it in one way or another.

Here are some commands you can try:

• echo "echo hello"> tryme Create a new file and add "echo hello" to it
• chmod 700 tryme Makes the new file executable
• tryme Execute the new file (should execute the command it contains and display "hello")
• ps aux Displays all running processes
• ps aux | grep $ USER Displays all running processes, but limits output to lines containing your username
• echo $ USER Displays your username using an environment variable
• whoami Displays your username with a command
• who | wc -l Counts currently logged in users

Synthesis

Once you get used to the basic commands, you can explore other commands and try to write scripts. You may realize that Linux is much more powerful and more enjoyable to use than you would imagine.