Linux Commands: 30 Commands Every Software Developer Should Know

Linux commands enable users to perform a wide range of tasks through the terminal, from file management to software development. But which Linux commands should you know, and how do you use them? In this guide, you will learn 30 essential Linux commands every developer should know, along with their functions and usage examples.

What Are Linux Commands?

Linux commands are instructions that allow users to interact with the operating system through a text-based interface. These commands are entered into an application called the terminal and processed by the system. This makes it possible to perform many tasks more quickly and consistently than through a graphical interface.

Developers use Linux commands to manage files, run applications, administer servers, and troubleshoot errors. Terminal proficiency is particularly important in web development, DevOps, cybersecurity, and cloud computing.

What Are the 30 Most Commonly Used Linux Commands?

A good starting point when learning Linux commands is to understand the basic commands used in everyday tasks. The commands below address different needs, including file and directory management, text processing, system monitoring, and networking.

1. What Does the pwd Command Do?

pwd (Print Working Directory) displays the directory you are currently in. It helps you check your current location, especially when working with multiple folders.

pwd

When you run this command, you may see a directory path such as /home/user/projects.

2. How Do You Use the ls Command?

ls lists the files and directories in a directory. You can also view file details and hidden files by using different options.

ls
ls -l
ls -a
ls -la

The -l option displays a detailed listing, while -a includes hidden files.

3. What Is the cd Command?

cd (Change Directory) allows you to navigate between directories. You can use it to enter a project folder or move to the parent directory.

cd projects
cd ..
cd ~

cd .. moves you up one directory, while cd ~ takes you to your home directory.

4. What Does the mkdir Command Do?

mkdir creates new directories. It is useful when organizing projects into structured folder hierarchies.

mkdir new-project
mkdir -p project/src/components

The -p option also creates any necessary parent directories.

5. How Do You Use the touch Command?

touch updates the timestamps of an existing file or creates an empty file if it does not exist.

touch app.py
touch index.html

This command provides a quick way to create a new file and get started.

6. What Is the cp Command?

cp copies files and directories. It can be used to create file backups or duplicate project files without moving the originals.

cp app.py app-backup.py
cp -r src src-backup

The -r option copies directories along with their contents.

7. What Does the mv Command Do?

mv is used to move or rename files and directories.

mv old.txt new.txt
mv report.txt documents/

In the first example, the file is renamed. In the second, the file is moved to another directory.

8. How Do You Use the rm Command?

rm deletes files. Different options can be used to remove directories.

rm temporary.txt
rm -r old-folder

Caution: Deleted files cannot always be recovered easily. Always verify the target path before running commands such as rm -r and rm -f.

9. What Is the cat Command?

cat displays the contents of text files in the terminal. It is useful for quickly inspecting small configuration files or source code.

cat README.md
cat config.txt

It can also display the contents of multiple files consecutively.

10. What Does the less Command Do?

less allows you to view long files page by page. It is particularly useful when reading large log files or lengthy documentation.

less application.log

Press / to search within the file and q to exit.

11. How Do You Use the head Command?

head displays the first lines of a file. By default, it shows the first 10 lines.

head application.log
head -n 20 application.log

The second example displays the first 20 lines of the file.

12. What Is the tail Command?

tail displays the last lines of a file. It is commonly used to check error messages added to application logs.

tail application.log
tail -f application.log

The -f option updates the output as new lines are added to the file.

13. What Does the grep Command Do?

grep searches files for specific words or text patterns. It can be used to find error messages or lines containing a particular function.

grep "ERROR" application.log
grep -in "timeout" application.log

The -i option ignores case differences, while -n displays the line number of each match.

14. How Do You Use the find Command?

find searches for files and directories based on specific criteria. You can search by filename or file type.

find . -name "*.py"
find . -type d

The first command searches the current directory and its subdirectories for Python files. The second lists directories.

15. What Is the chmod Command?

chmod changes file and directory permissions. It is used to control which users can read, modify, or execute files on Linux systems.

chmod +x script.sh
chmod 644 config.txt

+x adds execute permission. The 644 permission setting gives the file owner read and write permissions, while other users receive read permission.

16. What Does the chown Command Do?

chown changes the owner of a file or directory and, when needed, its group. It is particularly important in server administration and application deployment.

chown user file.txt
chown user:group file.txt

This operation generally requires sufficient administrative privileges.

17. How Do You Use the sudo Command?

sudo runs a command as another user with the required privileges, most commonly as an administrator. It is used for tasks such as changing system settings and installing packages.

sudo apt update

It is important to understand what a command does before running it with sudo. Administrative privileges allow changes that affect the entire system.

18. What Is the man Command?

man opens the manual pages for Linux commands. It is a reliable reference for learning about a command's options and functions.

man ls
man grep

Press q to exit the manual.

19. What Does the echo Command Do?

echo prints text or variable values to the terminal. It is commonly used to display simple output and messages in shell scripts.

echo "Hello Linux"
echo $HOME

The first example prints a message, while the second displays the user's home directory.

20. How Do You Use the wc Command?

wc counts lines, words, bytes, and other basic text statistics in a file. It can be used to analyze source code and text files.

wc README.md
wc -l app.py

The -l option returns the number of lines.

21. What Is the sort Command?

sort arranges text lines in a specified order. It can be used to sort lists alphabetically or compare numerical values.

sort names.txt
sort -n numbers.txt

The -n option sorts values numerically.

22. What Does the uniq Command Do?

uniq removes consecutive duplicate lines or displays how many times they occur. It is useful for log analysis and examining repeated records.

sort names.txt | uniq
sort names.txt | uniq -c

uniq only detects duplicates that appear next to each other. Therefore, sort is usually used first to identify all repeated lines.

23. How Do You Use the cut Command?

cut selects specific fields or character ranges from text lines. It can be used to extract desired columns from delimiter-separated files.

cut -d "," -f 1 users.csv

This command displays the first field in comma-separated lines. For complex CSV files, dedicated CSV tools may be more appropriate.

24. What Is the sed Command?

sed performs operations such as searching and replacing text in data streams. It is particularly useful for automating repetitive text-editing tasks.

sed 's/old/new/g' file.txt

This command replaces every occurrence of old with new in the output. Additional options are required to modify the file itself.

25. What Does the awk Command Do?

awk processes text by splitting it into fields and selecting lines that match specific conditions. It is especially useful for analyzing column-based data.

awk '{print $1}' data.txt

This example prints the first field of each line. By default, whitespace characters separate fields.

26. How Do You Use the ps Command?

ps provides information about system processes. It can be used to inspect running applications and identify individual processes.

ps
ps aux

ps aux displays a more detailed list of system processes. A process ID, or PID, is used to identify and track a process.

27. What Is the top Command?

top monitors running processes and system resource usage in real time. It is useful for investigating increases in CPU or memory consumption.

top

The display refreshes regularly. Press q to exit.

28. What Does the df Command Do?

df displays disk space usage across file systems. It is important for checking whether storage space is running low on servers.

df -h

The -h option displays sizes in human-readable units, such as KB, MB, or GB.

29. How Do You Use the du Command?

du shows how much disk space files and directories occupy. It can be used to identify large folders and investigate storage issues.

du -sh project/
du -h --max-depth=1

The -s option displays the total size, while -h uses human-readable units. The second command lists the sizes of directories one level below the current directory.

30. What Is the curl Command?

curl transfers data over various network protocols. Developers frequently use it to test API endpoints, inspect HTTP responses, and send requests to web resources.

curl https://example.com
curl -I https://example.com

The first command retrieves the response content. The -I option is used to display HTTP headers.

How Can You Combine Linux Commands?

One of the strengths of the Linux terminal is the ability to combine commands and perform multiple operations in a single line. This approach saves time, especially when analyzing logs, processing files, and performing automation tasks.

The | character, known as a pipe, is used to combine commands. It passes the output of one command as the input of the next.

For example:

grep "ERROR" application.log | sort | uniq

This command finds lines containing ERROR in the log file, sorts them, and removes consecutive duplicates. This makes error records easier to examine.

In another example, you can use find to locate specific files and wc to count them:

find . -name "*.py" | wc -l

This command returns the number of files with the .py extension in the current directory and its subdirectories.

What Should You Keep in Mind When Learning Linux Commands?

The most effective way to learn Linux commands is to practice them on real tasks. It is important to understand not only what commands do but also how their options behave and what results they can produce.

Keep the following points in mind when getting started:

• Practice in a safe environment: Use a virtual machine or test environment to experiment with file and directory operations.
• Learn command options: Explore how the same command behaves with different options.
• Use help resources: Learn how commands work through man and --help.
• Check file paths: Verify the target before deleting files or changing permissions.
• Combine commands in small steps: Start with simple operations using pipes and gradually build more comprehensive workflows.

Linux knowledge is valuable not only for Linux system administrators but also for software developers, test engineers, DevOps specialists, and professionals working with cloud technologies.

Using Linux commands regularly helps you work faster in the terminal and manage your development environment more effectively. Start with basic commands such as pwd, ls, and cd, then move on to tools such as grep, awk, and curl. Over time, you can also build your own automation workflows.