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NITRO(8) System Manager's Manual NITRO(8) NAME nitro -- a tiny but flexible init system and process supervisior SYNOPSIS nitro [dir] DESCRIPTION nitro is a service supervisor that can be used as a Unix init system. Every directory inside dir (by default: /etc/nitro) defines a service. When used as init, and the argument dir is `S' or `single', nitro looks at the directory /etc/nitro.single instead. This can be used to boot into a special single-user mode. SERVICE DIRECTORIES Service directories must have a name shorter than 64 characters and must not contain `,' or newlines in the file name. Service directories cannot be nested. Service directories can contain the following files: setup If it exists, this script is run when starting the service, the service enters state SETUP. When setup exits with status 111, the service enters state FATAL. When setup exits with state 0, the service progresses to state STARTING. Else, setup is restarted after a delay. run If it exists, this script should exec into the service. If this file does not exist, the service is a ONESHOT. When the service does not exit for 2 seconds, it enters state UP. log If this is a symlink to another service directory, the standard output of the service is connected to the standard input of the target service using a pipe. finish After the service has exited, this script is run with two argu- ments, the exit status of the service and the signal if the service exited due to a signal. Then, the service enters state DOWN. down If this file exists, the service is not brought up automati- cally. down-signal If this file exists, the first character of it encodes the sig- nal (see nitroctl(1)) that is sent to the service to bring it down, else SIGTERM. ENVIRONMENT NITRO_SOCK The control socket (by default: /var/run/nitro/nitro.sock) where nitro listens for commands sent by nitroctl(1). FILES The following special files are used inside the service directory: SYS/setup This script is run very early in boot, before all services are started. It can already start services using nitroctl(1). SYS/finish When system shutdown is requested, this script is run. When it exits, the remaining services are brought down. SYS/reincarnate If this script exists, nitro execs into it instead of rebooting or shutting down. SYS/final This script is run after all services are stopped. When it ex- its, the root file system is remounted read-only and the system shuts down/reboots. EXIT STATUS nitro tries hard not to exit, being used as pid 1. SEE ALSO nitroctl(1) AUTHORS Leah Neukirchen <leah@vuxu.org> FreeBSD ports 15.0 August 27, 2025 NITRO(8)
NAME | SYNOPSIS | DESCRIPTION | SERVICE DIRECTORIES | ENVIRONMENT | FILES | EXIT STATUS | SEE ALSO | AUTHORS
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