In The Complete Computing Environment there are a number of processes that I run that I want to have more visibility in to than if they were running as SystemD User Services. They may die, they may start to spawn errors, I want to know if it's failing or misbehaving. Right now this is mainly used in my OfflineIMAP setup, but I maintain it here and use it for one-off solutions.
(defun cce/async-forever (command buffer-name &optional seconds)
"Run a command in an async buffer forever"
(async-shell-command (concat "while true; do " command "; sleep " (prin1-to-string (or seconds 5)) "; done")
(get-buffer-create buffer-name)))