If you’re a software developer, you can’t avoid Linux. Created by Linus Torvalds, Linux is the preferred OS for most servers and the environment in which many popular development tools run best. While you don’t need to know everything about Linux, learning the top Linux commands is a valuable investment of your time.
With this post, you’ll have a handy guide to the Linux commands most often used. Starting with a quick introduction to Linux commands, we’ll dive right into the list of top commands, in a very hands-on way. Before wrapping up, we give you a cheat sheet of the top commands, so you can bookmark it and use it as reference.
To be able to follow this guide, you’ll need access to a Linux system. If you are not familiar with Linux, I suggest you download Ubuntu and run it in live mode on a USB stick. Many people consider Ubuntu to be the most user-friendly Linux distro, and running it without installing it is a nice, no-strings-attached way to get to know the system.
If you’re on Windows, there’s an even easier alternative: use WSL (Windows Subsystem for Linux).
Let’s get started.
If you have some familiarity working with the command line—even if it’s the Windows Command Prompt or Powershell—you might want to skip this section and go directly to “What Are the Basic Commands in Linux.”
So, what are Linux commands, and how do they work in practice? First, you need to know where to type them. If you’re running Ubuntu, search for an application called “Terminal.” In case you’re using WSL, just open Windows Terminal and start a new WSL tab.
Linux commands are usually small words or sequences of letters. You type them into your terminal and press the Enter key. That’s it. You might get some visual output from the command, but not always. If something goes wrong, the command will display an error message.
Also, many commands allow you to pass options to them, which can alter their behavior. For instance, after running the ls command inside a folder that contains files with different extensions, you’ll see a list of those files.
But let’s say I only wanted to see the .pdf files. I could do this:
ls *.pdfAnd as a result, I’d only see the .pdf files.
It’s also possible to chain commands to one another, sending—or “piping,” as people usually call it—the output of one command to the input of the next, creating flexible and powerful pipelines for text manipulation and other tasks.
Linux commands perform a wide variety of tasks, including text manipulation, file management, and networking. We’ll now cover some of the most commonly used commands, in no particular order. You’ll see each command’s explanation, followed by one or more examples.
Interestingly, many Linux commands have additional “side effects” beyond their primary function. For example, the touch command’s primary purpose is to update a file’s access and modification timestamps. However, if the specified file doesn’t exist, touch will create a new, empty file. As a result, many people associate touch with creating blank files.
In this guide, we’ll highlight these popular side effect usages in the headings, while the detailed explanations will cover the original purposes of the commands.
As you’ve seen, the ls command lists the content of the current directory. Some examples:
List the contents of the current directory
lsOr list the contents of the current directory with the extension .java
ls *.javaList all files, including hidden ones
ls -aList the contents of a child directory ls subfoldername
The clear command has a self-explanatory name: it clears the screen of all the outputs from previous commands.
This is the command you use to change directories. In other words, to move to or from a given path.
Examples:
Move to the user home directory
cd ~Move to the specified path
cd /home/johndoe/somefolderOr move one level up from the current directory
cd ..Go back to the previous directory
cd -You use mkdir to create one or more new directories.
Examples:
Create a new directory
mkdir new-folderTry to create the same one again and get the error
mkdir new-folder
mkdir: cannot create directory ‘new-folder’: File existsCreate three new directories
mkdir folder1 folder2 folder3Create a whole path of directories
mkdir -p root/child/grandchildrm is the command you use to delete files and directories.
Examples:
Remove a single file
rm file.txtRemove an empty directory
rm -d folderOr, remove a non-empty directory and all its contents, recursively.
rm -r non-empty-folderThe touch command is meant to change the access and modification times of the specified file to the time of execution. If the specified file doesn’t exist, touch creates it. That’s why this command is often used to create empty files.
Example:
Create an empty file
touch yet-another-file.txtYou use the cp command when you want to copy files or directories.
Examples:
Copy a file
# Create an empty file named "file1.txt"
touch file1.txt
# List the contents of the current directory
ls
# Output: file1.txt
# Copy "file1.txt" to a new file named "file2.txt"
cp file1.txt file2.txt
# List the contents of the current directory again
ls
# Output: file1.txt file2.txtCopy a directory and its contents
cp -r cpdemo cpdemo2You use the mv command to move or rename files. The command is the same because, from the OS’s point of view, the operation is identical.
Example:
Rename a single file
mv original-name.txt new-name.txtpwd stands for print working directory, and that’s what it does: it tells you the path where you’re currently at.
Example:
pwd
/home/username/demo/cpdemo2echo – Write something to the standard output
The echo command displays something to the standard output and is very useful to display messages when creating scripts to automate administrative tasks. You can also pipe the output of echo to a file, which results in a file being created with that content.
Examples:
Display a message
echo Hello, world!Create a file with the given content
echo content > new-file.mdThe cat command is meant to concatenate files and display the result to the standard output. If only one file is specified, the command then displays its contents to the standard output. That’s why people often refer to cat as the command to display a file, forgetting its concatenation capability.
Examples:
Display the content of a file
echo Hello, world! > new-file.md
cat new-file.md
Hello, world!Concatenate two files and displays the resulting content
echo Hello > hello.txt
echo ", World!" > world.txt
cat hello.txt world.txt
Hello
, World!Concatenate two files and sends the result to a new file
cat hello.txt world.txt > helloworld.txt
cat helloworld.txt
Hello
, World!| Command | Description | Example |
| ls | List directory contents | ls -l |
| clear | Clear the terminal screen | clear |
| cd | Change directory | cd /path/to/directory |
| mkdir | Create a new directory | mkdir newdir |
| rm | Remove files or directories | rm -r directory_name |
| touch | Create an empty file or update the timestamp of an existing file | touch newfile.txt |
| cp | Copy files or directories | cp file.txt /path/to/destination |
| mv | Move or rename files or directories | mv oldname.txt newname.txt |
| pwd | Print working directory | pwd |
| echo | Display a line of text | echo “Hello, World!” |
| cat | Concatenate and display files | cat file.txt |
There are many Linux commands, and most can be used with options that elevate the number of variations to staggering numbers. In this post, we’ve shown you some of the most important commands, but we’ve barely scratched the surface of all Linux has to offer.
For instance, an important command that didn’t make it to our list is the tail command: it allows you to display the last 10 lines of a file to standard output. The tail command also has an option that, when used, keeps appending data to the output as the file grows. This command is very useful when handling log files. And speaking of logs, we also suggest this article on Linux logs.
Finally, to keep all your applications running on Linux performing at their best, check out Stackify Retrace. Better still, start your free trial of Stackify Retrace today and see how full lifecycle APM helps you maintain code quality and performance.
Stackify's APM tools are used by thousands of .NET, Java, PHP, Node.js, Python, & Ruby developers all over the world.
Explore Retrace's product features to learn more.
If you would like to be a guest contributor to the Stackify blog please reach out to [email protected]
