List of most useful Linux commands

View Active Processes

Displays the processes that are running on the system.

ps aux

Terminate a Process

Ends a specified process by its PID.

kill PID

Run a Process in the Background

Sends a command to the background.

command &

List Background Jobs

Displays the processes that are in the background.

jobs

Bring a Background Process to the Foreground

Restores a process to the foreground.

fg %n

View CPU and Memory Usage

Displays real-time CPU and memory usage of the system.

top

Detailed Memory Information

Shows details of memory usage.

free -h

Show Disk Space

Verifies disk space usage by partition.

df -h

System Information

Displays details about the operating system and hardware.

uname -a

View System Logs

Checks the system logs.

dmesg

List Files

Lists the files in a directory, including hidden ones.

ls -la

Move Files or Directories

Moves files or directories to another location.

mv source destination

Copy Files

Copies files or directories.

cp file destination

Delete Files or Directories

Deletes files (or directories with the -r option).

rm file

Create Directory

Creates a new directory.

mkdir directory_name

Show File Content

Displays the content of a text file.

cat file

Show First Lines of a File

Displays the first 10 lines of a file.

head file

Show Last Lines of a File

Displays the last 10 lines of a file.

tail file

Concatenate and Show Files

Concatenates the content of files.

cat file1 file2

View Real-Time Updates of a File

Displays the content of a file that is being updated, useful for logs.

tail -f file

Find a File by Name

Searches for files by name in a directory and its subdirectories.

find /path -name "file_name"

Search Within File Content

Searches for a string of text in files within a directory.

grep "text" *.txt

Find Recently Modified Files

Finds files modified within a specific time range.

find /path -mtime -n

Add a New User

Creates a new user on the system.

sudo adduser username

Change a User’s Password

Changes a user’s password.

passwd username

Add a User to a Group

Adds a user to a specific group.

sudo usermod -aG group_name username

Delete a User

Removes a user from the system.

sudo deluser username

Change Permissions of a File

Changes the permissions of a file or directory (read, write, execute).

chmod 755 file

Change the Owner of a File

Changes the owner and group of a file.

chown user:group file

View File Permissions

Displays permissions and details of files.

ls -l

Compress Files in tar.gz

Creates a compressed file in tar.gz format.

tar -czvf file.tar.gz file

Decompress tar.gz Files

Extracts files from a tar.gz file.

tar -xzvf file.tar.gz

Compress Files in zip

Creates a compressed file in zip format.

zip file.zip file

Decompress zip Files

Extracts files from a zip file.

unzip file.zip

Update Repositories

Updates the list of available packages.

sudo apt update

Install a Package

Installs a package from the repositories.

sudo apt install package_name

Remove a Package

Uninstalls a package from the system.

sudo apt remove package_name

Upgrade the Entire System

Upgrades all installed packages to the latest version.

sudo apt upgrade

Mount a File System

Mounts a device or partition to a directory.

sudo mount /dev/device /mount_point

Unmount a File System

Unmounts a device or partition.

sudo umount /dev/device

View Mounted File Systems

Displays the currently mounted file systems.

mount

Format a Partition

Formats a partition to a specific file system.

sudo mkfs -t ext4 /dev/device