apt(Advantage package system) command is used for interating with dpkg(packaging system used by debian). There is already dpkg command to manage .deb packages. But apt is more user-friendly and efficient way.
In simple terms apt is a command used for installing, deleting and other operations on debian based Linux.
You will be using apt command mostly with sudo privileges.
install followed by package_name is used with apt to install new package.
sudo apt install package_name
sudo apt-get install g++
This command will install g++ on your system.
remove followed by package_name is used with apt to remove specific package.
sudo apt remove package_name
sudo apt-get remove g++
This command will remove g++ from your system.
Whenever a new package that depends on other packages is installed on the system, the package dependencies will be installed too. When the package is removed, the dependencies will stay on the system. This leftover packages are no longer used by anything else and can be removed.
sudo apt autoremove
This command will remove all unused from your system.
apt package index is nothing but a database that stores record of available packages that are enabled on your system.
sudo apt update
This command will package index on your system.
If you want to install latest update for your install packages you may wanna run this command.
sudo apt upgrade
The command doesn’t upgrade packages that require removal of installed packages.
If you want to upgrade a single package, pass the package name:
sudo apt upgrade package_name
This command will upgrade your packages to latest version.