Package Installation

Debian / Ubuntu: APT

apt update

apt install package-name

# Multiple packages together
apt install nginx curl wget git unzip

apt upgrade -y

# Full upgrade (includes kernel and changed dependencies)
apt full-upgrade -y

apt remove package-name

# Also remove configuration files
apt purge package-name

# Remove packages that are no longer needed
apt autoremove -y

apt search keyword

dnf install package-name -y

dnf update -y

dnf remove package-name

dnf search keyword

# Debian/Ubuntu
dpkg -S $(which command)

# CentOS
dnf provides command

# Debian/Ubuntu
dpkg -l | grep name

# CentOS
rpm -qa | grep name

For software that is not in standard repositories, you often use:

Snap:

apt install snapd
snap install package-name

Flatpak (less common on servers):

apt install flatpak

From source or script:

# Example: installing Node.js via official script
curl -fsSL https://deb.nodesource.com/setup_20.x | bash -
apt install -y nodejs

Before executing scripts from the internet with curl | bash, always verify that the source is official and trustworthy.