15 Essential Linux Commands Every LINUX User Should Know

 1.last 

    Displays a list of the most recent user logins on the system.

Example:

2.hostnamectl

    Shows or changes the system’s hostname and OS information.

Example:

    

3.alias update='sudo apt update && sudo apt upgrade -y'

    Creates a shortcut (alias) for updating and upgrading all system packages.

Example:

    

4.lsblk

    

    Lists all block storage devices (like hard drives and partitions).

    

Example:

    

5.chmod +x

    Gives execute (run) permission to a script or file.

Example:

    

    

6. top

    Displays real-time system resource usage — like CPU, memory, and running processes.

Example: 

7. free -h 

    Shows the system’s memory usage (RAM and swap) in a human-readable format.

Example:

    

8.uname -a 

    Displays detailed system information such as kernel version, OS type, and architecture.

Example:

    

9.df -h

    Shows disk space usage for all mounted file systems.

Example:

    

  

10. tree

    Displays the directory structure in a tree-like format.

    Example:

    

    

11. pwd

    

    Prints the current working directory (your location in the terminal).

Example:

    

12.cat 

    Displays the content of a file directly in the terminal.

Example:

    

13.dpkg -l 

    Lists all installed packages in Debian or Ubuntu systems.

Example:

    

    

14.dmidecode

    Displays detailed hardware information such as BIOS version, motherboard, and CPU details.

Example:

    

15.journalctl -xe

    Shows detailed system logs and error messages.

Example: