What do +,- and ? symbols represent in service --status-all represent in Ubuntu 14.04. I am not able to understand it properly. I guess + here might mean delayed services which start after the system startup.Similarly, - would mean services running at startup.No idea about the ? symbol. Somebody please help me identifying symbols. 
What do +,- and ? symbols represent in `service --status-all`
ubuntu;services;upstart
From: /usr/sbin/service#printf  %s %-60s %s\n [?] $SERVICE: unknown 1>&2#printf  %s %-60s %s\n [+] $SERVICE: running#printf  %s %-60s %s\n [-] $SERVICE: NOT running[?] means the service status isn't known (the init file does not output a status)[+] means the service is running[-] means the service is not runningEdit, this was also answered here: https://superuser.com/questions/367863/how-do-interpret-the-output-of-service-status-all