so you've got a process that you want to keep running. you might have it in a tmux or screen session. let's use systemd user units to manage it!
ensure that your user unit loadpath is set up:
mkdir -p ~/.config/systemd/user/
create a basic service. save something like this in
~/.config/systemd/user/my-new-service.service
(using the name of the unit
you're creating)
[Unit]
Description=foo
[Service]
ExecStart=/bin/bash -c "while true do; echo hi; done"
[Install]
WantedBy=default.target
enable it
systemctl --user enable --now my-new-service.service
enable-linger for your user account
loginctl enable-linger
this allows your user units to run even when you're not logged in.
done!
you can now use systemctl --user
to manage your daemonized process.
pro-tip: add alias sysu='systemctl --user'
to your shell's configuration
for a handy shortcut (or any other alias as you choose)