apt — Package Management on Debian & Ubuntu

sudo apt update                  # Refresh package list from repos
sudo apt upgrade                 # Upgrade all installed packages
sudo apt install nginx           # Install a package
sudo apt remove nginx            # Remove (keep config files)
sudo apt purge nginx             # Remove + delete config files
sudo apt autoremove              # Remove unused dependencies
sudo apt search "text editor"    # Search available packages
apt show nginx                   # Show package details
apt list --installed             # List all installed packages
apt list --upgradable            # List packages with updates

# Update + upgrade in one go
sudo apt update && sudo apt upgrade -y

# Install multiple packages
sudo apt install nginx php mysql-server

# Install specific version
sudo apt install nginx=1.18.0-0ubuntu1

# Fix broken dependencies
sudo apt --fix-broken install

# Clean download cache
sudo apt clean
sudo apt autoclean

sudo dpkg -i package.deb         # Install a .deb file manually
dpkg -l                          # List all installed packages
dpkg -L nginx                    # List files installed by a package
dpkg -S /usr/bin/vim             # Which package owns this file?
sudo dpkg -r package             # Remove package