Another day, another attempt to rewrite the world a little bit less and use an existing standard tool, because that's what they were made for...

... and another failure. kill does not have a portable way of sending a numbered signal to a process. When you have a signal number, you can use the kill() system call to send that signal to a process, but not the kill command-line utility.

Yes, I understand that you are supposed to address signals by their name and not by their number, but since the system call uses numbers in the first place, would it have been so horrible to allow the command line to do the same? And so, I am now writing a s6-frontend-kill command line helper.