launch_detached(
cmd,stdin,stdout,stderr,...) ->ok,err
Fork and execute a command that nobody will wait for
Like launch, but the command starts from a short-lived intermediate
child in a session of its own, so it is reparented to init and reaped
there. Use it for processes the caller never waits for -- external
openers, delayed notifications -- which would otherwise linger as
zombies for as long as the caller lives, and would take the caller's
terminal signals with them.
The command's own PID is not reported: it is a grandchild, not a child.