pacman

Packages are kept in /var/cache/pacman/pkg.

Delete unused old packages with:

1sudo pacman -Sc

Signatures are handled by the pacman-key, initially set up with:

1sudo pacman-key --populate archlinux

And refreshed with:

sudo pacman-key --refresh-keys

If you have usigned keys, you can refresh with:

1sudo pacman -Sc

or

1sudo pacman -Scc

Reset all keys with:

1sudo rm -r /etc/pacmand.d/gnupg/ && sudo pacman-key --init

If you're constantly getting 'everything corrupted, nothing upgraded', try running:

1sudo pacman -S archlinux-keyring

List all orphaned packages:

1sudo pacman -Qtdq

Cleaning Config Files

Arch does not overwrite your changes to configuration files. Instead, it updates them by adding the .pacnew suffix.

So when /etc/pacman.conf receives an update, this will be placed in /etc/pacman.conf.pacnew. These changes must be merge manually.

Install the pacdiff tool to make this easier, from the pacman-contrib package, then simply run sudo pacdiff to sort through the various mergers.