APT Package Manager in Debian

APT package manager in Debian systems can be used to download and install packages from online repositories. The APT commands (apt-get, apt-cache, and so on) can be used to install packages locally. However, it’s normally used for working with online software.
sudo apt-get update
Consults /etc/apt/sources.list and updates the database of available packages. Be sure to run this command whenever sources.list is changed.
apt-cache search
Case-insensitive search of the package database for the keyword given. The package names and descriptions are returned where that keyword is found.
sudo apt-get install
Download and install the given package name as found in the package database.
sudo apt-get -d install
Download the package only, placing it in /var/cache/apt/archives.
apt-cache show
Display information about the software from the named package.
sudo apt-get upgrade
Check updates for all installed packages and then prompt to download and install them.
sudo apt-get dist-upgrade
Updates the entire system to a new release, even if it means removing packages. (Are you on nuts to do this?)
sudo apt-get autoclean
Can be run anytime to delete partially downloaded packages, or packages no longer installed.
sudo apt-get clean
Removes all cached packages from /var/cache/apt/archives to free up disk space.
sudo apt-get –purge remove
Remove the named package and all its configuration files. Remove the –purge keyword to keep config files.
sudo apt-get -f install
Do a sanity check for broken packages. This tries to fix any “unmet dependency” messages.
apt-config -V
Print version information of installed APT utilities.
sudo apt-key list
List gpg keys that APT knows about.
apt-cache stats
Print statistics on all packages installed.
apt-cache depends
Print dependencies for a package (whether it’s installed or not).
apt-cache pkgnames
List all packages installed on the system.