Protonvpn again
I was running protonvpn-cli https://forum.artixlinux.org/index.php/topic,3284.msg22591.html#msg22591 Yesterday it gave an "externally managed environment" error, which means that the app now is required to run in a virtual environment, I think. I don't know if this is related to stradjer's warning in the thread. This was new to me, so I'll post my results here in case it's useful for someone.
I found two ways to run protonvpn:
$ python3 -m venv /path
$ path/bin/pip3 install protonvpn-cli
$ sudo /path/bin/protonvpn c -f # connect with fastest server
Or, python-pipx automates the process somewhat. It creates .local/pipx which contains venvs/protonvpn-cli, and a link in .local/bin
$ pipx install protonvpn-cli
$ sudo ~/.local/bin/protonvpn c -f
My configuration from before still worked, I didn't have to do protonvpn init again.
As people said in the thread, the vpn can be launched from network-manager or from open-vpn, but an advantage of protonvpn-cli is that it chooses the fastest available server. I'm not entirely sure it's worth 35MB of disk space, though.
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Edit : as of March 2024, the community protonvpn-cli no longer connects due to changes at protonvpn. The official cli requires systemd. https://www.reddit.com/r/ProtonVPN/comments/1bd1o4e/protonvpn_cli_api_not_working/