Editing Arch Linux Basics (section)

=== Pacman ===
<code>sudo pacman -Syu</code>: updates the system (HIGHLY RECOMMENDED to make sure to do this BEFORE installing/updating a new or already installed package - see [https://wiki.archlinux.org/index.php/System_maintenance#Partial_upgrades_are_unsupported "partial upgrades are not supported" on Archwiki]. It will become second nature once you do it often. Auto updates generally break your system on occasion (and output from console is helpful when updating packages) so they're not recommended.)
<code>sudo pacman -S [package]</code>: installs a specific package
<code>sudo pacman -R [package]</code>: removes a specific package
<code>sudo pacman -Rs [package]</code>: removes a specific package AND ALL of its dependencies (be careful! important ones might also get removed! Look at the package list FIRST.)

<code>sudo rm -rf /var/lib/pacman/sync/*</code>: removes package cache files. You will need to redownload them using <code>sudo pacman -S</code> or when installing a package, use <code>sudo pacman -S [package]</code>. This happens when you either get an unreliable or blocked network connection that you can't connect to the Arch repos properly (e.g. in an airport, or any other paid/restricted internet connection, or while stuck in a captive portal webpage) and the package files become corrupt.

<code>sudo pacman -U [package file with .tar.xz]</code>: installs a downloaded .tar.xz package from arch package repositories (instructions needed - from package browser on arch linux website --> download snapshot button (AUR)/download from mirror (package browser)). Can also reinstall downloaded local packages from /var/cache/pacman/pkg. (use cd to go to this directory.)