How to install an application from archlinux.org

As any other AUR package (you even tagged aur, so I’ll assume you’ll know what that means), as documented on https://wiki.archlinux.org/title/Arch_User_Repository :

1. Get the PGP key
2. get the AUR source files by cloning the appropriate https://aur.archlinux.org/{…}.git; check the PGP signature
3. do the build using makepkg in the directory you just cloned. As usual on arch, you need to remember the flags that everyone always needs to use, iirc these are makepkg -s -r -c. And if you’re doing a new build, you’d still want to git clean -xdf, because this is very mature, very clean and very reliable package building…
4. install the package you just built using pacman -U ….pkg.tar.zst

I cannot stress enough how finicky all this is. If you run an update of your system (which you basically need to do every time you install a new package), the dependencies of your self-built package might (will!) break, and you need to do a fresh build. But you won’t hear about that from pacman; things just… break.

I have git config --global url.https://aur.archlinux.org/.insteadof aur: set up, and build my aur-sourced packages under my ~/aur directory, so for me,

$ cd ~/aur
$ git clone aur:intellij-idea-ultimate-edition
$ cd intellij-idea-ultimate-edition    # or ${_:4}, retype the name howsomever
$ makepkg -si

was all it took. There’s AUR helpers for automatically hunting down dependencies that are themselves AUR packages and installing them with –asdeps and such, I don’t use enough AUR packages to make bothering with one worthwhile and it’s completely unnecessary here.

If you don’t plan to use an AUR helper, you can simply build the package from source by running(using the package you gave here as an example):

git clone https://aur.archlinux.org/packages/intellij-idea-ultimate-edition
cd intellj-idea-ultimate-edition
makepkg
pacman -U intellij-idea-ultimate-edition-2023.2.1-x86_84.pkg.tar.zst

If you do want an AUR helper, I’d highly recommend aurutils, as it integrates directly with pacman, instead of trying to just act like pacman.

After you’ve installed it, Aurutils requires you to setup a local repo, and they have instructions for this and more advanced usuage in the bundled man pages
but the basics of it are:
Add this to the bottom of /etc/pacman.conf
(the local repository root is /home/custompkgs here but you can keep it in any dir you want to)

[custom]
    SigLevel = Optional TrustAll
    Server = file:///home/custompkgs

Create the repo root and database:

sudo install -d /home/custompkgs -o $USER
repo -add /home/custompkgs/custom.db.tar.gz

If there are any built packages, add them to the database:

cd /home/custompkgs
repo -add -n custom.db.tar.gz *.pkg.tar*

And then sync pacman by running sudo pacman -Syu
To install packages with aurutils, just run aur sync {name of package} and then pacman -S {name of package}