How can the *shell command output* buffer be kept in the background?

shell-command takes an optional argument OUTPUT-BUFFER where you can specify the buffer to output to. If it is t (actually not a buffer-name and not nil) it will be output in the current buffer. So we wrap this into a with-temp-buffer and will never have to bother with it:

(with-temp-buffer
  (shell-command "cat ~/.emacs.d/init.el" t))

Maybe using shell-command was the root of the problem. I think I found a solution with call-process which works, although there may be a more elegant way:

(call-process-shell-command
 "cat ~/.emacs.d/init.el"
 nil "*Shell Command Output*" t
 )