Pacman

Sync the file database for the first time

pacman -Fy

Upgrade packages

pacman -Syu

Search for a package

How to look for a repository package:

pacman -Fs package_name

pacman -Ss package_name

pacman -Si package_name

How to check if a package is installed:

pacman -Qi package_name

Install a package

pacman -S package_name

Remove a package

pacman -R package_name

More info: https://wiki.archlinux.org/index.php/pacman#Search_for_a_package_that_contains_a_specific_file

How to clean package cache

Check how many cached packages are in the cache folder:

$ sudo ls /var/cache/pacman/pkg/ | wc -l

Check the total disk space used by the cache folder:

$ du -sh /var/cache/pacman/pkg/

Clean all packages, except the 3 most recent versions:

$ sudo paccache -r