The 40 Essential Linux Commands Every User Should Know

Linux is a family of open-source operating systems based on the Linux kernel. Distributions like Ubuntu, Fedora, Debian, and Red Hat are widely used on servers, mobile devices, and personal computers. One of the most powerful and distinctive features of Linux is its command-line interface (CLI), which allows users to interact directly with the operating system through text commands.

While graphical user interfaces (GUIs) make many tasks more accessible, mastering the command line offers deeper and more efficient control over the system. It allows you to automate processes, manage systems remotely, and perform tasks that may not be available through the GUI.

In this article, we will explore 40 essential Linux commands that every user should know. These commands will help you navigate the file system, manage processes, manipulate files, and much more. Additionally, we will provide practical examples and additional tips to get the most out of each command.

What is a Linux Command?

A Linux command is an instruction entered into the terminal to perform a specific task. The terminal is a text-based interface that allows users to interact directly and efficiently with the operating system. Through commands, you can run programs, manage files, configure systems, and perform virtually any task in Linux.

The general syntax of a Linux command is:

command_name [options] [arguments]

• command_name: The program or utility you want to execute.
• options: Modifiers that alter the behavior of the command. They usually start with one or two dashes (e.g., -a or --all).
• arguments: Files, directories, or other data on which the command acts.

It is important to remember that Linux distinguishes between uppercase and lowercase letters, so ls and LS are different commands.

The 40 Most Used Linux Commands

Below is a detailed list of the most essential Linux commands, organized to facilitate understanding and use.

1. sudo Command

Allows users to run programs with the security privileges of another user, typically the superuser (root).

Syntax:

sudo [command]

Example:

sudo apt-get update

This command updates the list of available packages on the system.

Tip: Use sudo with caution, as it executes commands with elevated privileges.

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2. pwd Command

Displays the full path of the current working directory.

Syntax:

pwd

Example:

/home/user

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3. cd Command

Changes the current working directory.

Syntax:

cd [path]

Examples:

• Go to the Documents directory:

  cd Documents
  

• Return to the previous directory:

  cd ..
  

• Go to the home directory:

  cd ~
  

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4. ls Command

Lists files and directories in the current directory.

Syntax:

ls [options] [path]

Examples:

• List in detailed format:

  ls -l
  

• Include hidden files:

  ls -a
  

• List with human-readable sizes:

  ls -lh
  

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5. cat Command

Displays the content of files, concatenates files, and redirects outputs.

Syntax:

cat [options] [file...]

Examples:

• Display the content of a file:

  cat file.txt
  

• Combine files:

  cat file1.txt file2.txt > combined.txt
  

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6. cp Command

Copies files and directories.

Syntax:

cp [options] source destination

Examples:

• Copy a file:

  cp file.txt /path/to/destination/
  

• Copy a directory:

  cp -r source_folder destination_folder
  

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7. mv Command

Moves or renames files and directories.

Syntax:

mv [options] source destination

Examples:

• Move a file:

  mv file.txt /path/to/destination/
  

• Rename a file:

  mv old_name.txt new_name.txt
  

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8. mkdir Command

Creates new directories.

Syntax:

mkdir [options] directory_name

Examples:

• Create a directory:

  mkdir new_folder
  

• Create nested directories:

  mkdir -p project/{src,bin,doc}
  

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9. rmdir Command

Deletes empty directories.

Syntax:

rmdir [options] directory_name

Example:

rmdir empty_folder

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10. rm Command

Deletes files and directories.

Syntax:

rm [options] file_or_directory

Warning: This command deletes permanently.

Examples:

• Delete a file:

  rm file.txt
  

• Delete a directory and its contents:

  rm -r folder
  

• Force deletion without confirmation:

  rm -rf folder
  

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11. touch Command

Creates empty files or updates the timestamp of existing files.

Syntax:

touch file_name

Example:

touch new_file.txt

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12. locate Command

Searches for files by name.

Syntax:

locate [options] pattern

Example:

locate document.pdf

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13. find Command

Searches for files and directories in a hierarchy.

Syntax:

find [path] [conditions]

Examples:

• Search for files by name:

  find /path -name "file.txt"
  

• Search for files by size:

  find /path -size +100M
  

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14. grep Command

Searches for text patterns within files.

Syntax:

grep [options] pattern [file...]

Examples:

• Search for a word in a file:

  grep "error" log.txt
  

• Search recursively:

  grep -r "function" /path/project
  

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15. df Command

Displays information about the file system usage.

Syntax:

df [options]

Example:

df -h

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16. du Command

Reports disk space usage.

Syntax:

du [options] [path]

Examples:

• Show the size of a folder:

  du -sh folder
  

• List sizes of subdirectories:

  du -h folder
  

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17. head Command

Displays the first lines of a file.

Syntax:

head [options] [file]

Example:

head -n 20 file.txt

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18. tail Command

Displays the last lines of a file.

Syntax:

tail [options] [file]

Examples:

• Show the last 10 lines:

  tail file.txt
  

• Follow updates in real-time:

  tail -f log.txt
  

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19. diff Command

Compares files line by line.

Syntax:

diff [options] file1 file2

Example:

diff original.txt modified.txt

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20. tar Command

Archives and compresses files.

Syntax:

tar [options] archive.tar [files]

Examples:

• Create a tar archive:

  tar -cvf archive.tar folder/
  

• Extract a tar archive:

  tar -xvf archive.tar
  

• Compress with gzip:

  tar -czvf archive.tar.gz folder/
  

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21. chmod Command

Changes file and directory permissions.

Syntax:

chmod [options] mode file_or_directory

Example:

chmod 755 script.sh

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22. chown Command

Changes the owner and group of files and directories.

Syntax:

chown [options] user[:group] file_or_directory

Example:

chown user:group file.txt

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23. jobs Command

Displays background jobs in the current session.

Syntax:

jobs [options]

Example:

jobs

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24. kill Command

Sends signals to processes.

Syntax:

kill [options] PID

Example:

kill 12345

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25. ping Command

Checks connectivity with a host.

Syntax:

ping [options] destination

Example:

ping www.google.com

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26. wget Command

Downloads files from the internet.

Syntax:

wget [options] URL

Example:

wget https://example.com/file.zip

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27. uname Command

Displays system information.

Syntax:

uname [options]

Example:

uname -a

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28. top Command

Monitors processes in real-time.

Syntax:

top

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29. history Command

Shows the command history.

Syntax:

history

Example:

history

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30. man Command

Displays the user manual of commands.

Syntax:

man command

Example:

man ls

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31. echo Command

Displays text in the standard output.

Syntax:

echo [options] text

Example:

echo "Hello World"

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32. zip and unzip Commands

Compress and decompress files in ZIP format.

Syntax:

• Compress:

  zip [options] archive.zip files
  

• Decompress:

  unzip [options] archive.zip
  

Examples:

• Compress:

  zip files.zip file1.txt file2.txt
  

• Decompress:

  unzip files.zip
  

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33. hostname Command

Displays or sets the hostname.

Syntax:

hostname [new_name]

Example:

hostname

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34. useradd and userdel Commands

Manage user accounts.

Syntax:

• Add user:

  sudo useradd [options] username
  

• Delete user:

  sudo userdel [options] username
  

Examples:

• Add user:

  sudo useradd john
  

• Set password:

  sudo passwd john
  

• Delete user:

  sudo userdel john
  

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35. apt-get Command

Manages packages on Debian-based systems.

Syntax:

sudo apt-get command [package]

Examples:

• Update package list:

  sudo apt-get update
  

• Install a package:

  sudo apt-get install package_name
  

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36. Text Editors nano, vi, and gedit

Allow editing text files from the terminal or with a graphical interface.

Examples:

• Use nano:

  nano file.txt
  

• Use vi:

  vi file.txt
  

• Use gedit (graphical interface):

  gedit file.txt
  

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37. alias and unalias Commands

Create and remove aliases for commands.

Syntax:

• Create alias:

  alias alias_name='command'
  

• Remove alias:

  unalias alias_name
  

Example:

alias ll='ls -la'

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38. su Command

Switches to another user in the current session.

Syntax:

su [options] [username]

Example:

su -

Switches to the root user.

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39. htop Command

Monitors processes with an interactive interface.

Syntax:

htop

Note: You may need to install it:

sudo apt-get install htop

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40. ps Command

Displays information about active processes.

Syntax:

ps [options]

Example:

• Show all processes:

  ps -e
  

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Additional Tips and Tricks

• Clear the terminal screen: Use clear or Ctrl + L.
• Autocomplete commands and paths: Press Tab.
• Cancel a running command: Press Ctrl + C.
• Pause a running process: Press Ctrl + Z.
• Resume a background process: Use bg.
• Bring a process to the foreground: Use fg.
• Freeze the terminal: Press Ctrl + S.
• Unfreeze the terminal: Press Ctrl + Q.
• Navigate to the beginning or end of the line: Use Ctrl + A and Ctrl + E.
• Run multiple commands in one line: Separate with ; or use && to execute the next only if the previous succeeds.

List of Linux Commands

Command	Usage
alias	Creates an alias to run a command.
apt-get	Manages packages resolving dependencies.
cat	Displays, combines, and creates files.
cd	Changes directory.
chmod	Modifies read, write, and execute permissions.
chown	Changes the owner and group of files or directories.
cp	Copies files or directories and their content.
df	Reports disk space usage.
diff	Compares files or directories.
du	Checks how much space a file or directory occupies.
echo	Displays a string of text.
find	Searches for files and directories.
grep	Searches for text strings within files.
head	Displays the first lines of a file.
history	Lists previously executed commands.
hostname	Displays or sets the system’s hostname.
htop	Monitors system resources and server processes.
jobs	Shows background processes running in the shell.
kill	Manually terminates a non-responsive program.
locate	Finds files on the system.
ls	Displays the contents of a directory.
man	Provides a user manual of a command or utility.
mkdir	Creates one or more directories.
mv	Moves or renames files and directories.
nano, vi, gedit	Text editors.
ping	Checks network connectivity with another host.
ps	Produces a snapshot of running processes.
pwd	Displays the path of the current working directory.
rm	Deletes files or directories.
rmdir	Deletes empty directories.
su	Allows using another user’s shell.
sudo	Executes commands with administrative privileges.
tail	Displays the last lines of a file.
tar	Compresses and decompresses tar files.
top	Displays running processes in real-time.
touch	Creates an empty file or updates its timestamp.
unalias	Removes an existing alias.
uname	Prints system and hardware information.
unzip	Decompresses zip files.
useradd, userdel	Adds or deletes user accounts.
wget	Downloads files from the web.
zip	Compresses multiple files into a zip archive.

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Mastering these Linux commands will allow you to take full advantage of the power and flexibility that the operating system offers. The command line is an essential tool for system administrators, developers, and anyone looking to interact efficiently with Linux.

I recommend practicing regularly and exploring the different options each command offers. Feel free to consult the manual pages with man [command] for detailed information.

Dive into the world of Linux and discover all you can achieve with these essential commands!