I've got an existing Arch Linux installation. After booting from the installation media, is there some way to install software either from the installation media or using the network I've set up using the installation media (that is, without setting up networking again after an arch-chroot)? The use case is that my installation with the base system doesn't seem to have the wireless_tools package installed which seems to be necessary to get a wireless connection. Since setting up a wired connection is infeasible at the moment, it would be great to use the boot disk for this.
How to install software from Arch boot disk to existing Arch system?
arch linux;package management;pacman
First of all, the network persists even when you arch-chroot. But if you still want the answer, just use pacman --root /wherever/your/install/is/mounted.See also man pacstrap.