Init files shall accept one argument, saying what to do:
| start | start the service |
| stop | stop the service |
| restart | stop and restart the service if the service is already running, otherwise start the service |
| reload | cause the configuration of the service to be reloaded without actually stopping and restarting the service |
| force-reload | cause the configuration to be reloaded if the service supports this, otherwise restart the service |
| status | print the current status of the service |
The start, stop, restart, force-reload, and status commands must be supported by all init files; the reload option is optional. Other init script actions may be defined by the init script.
Init files must ensure that they will behave sensibly if invoked with start when the service is already running, or with stop when it isn't, and that they don't kill unfortunately-named user processes. The best way to achieve this is to use the init-script functions provided by /lib/lsb/init-functions.
If a service reloads its configuration automatically (as in the case of cron, for example), the reload option of the init file must behave as if the configuration has been reloaded successfully.
These executable files must not fail obscurely when the configuration files remain but the package has been removed, as the default in [the packaging system] is to leave configuration files on the system after the package has been removed. Only when it is executed with the [purge] option will [the packaging system] remove configuration files. Therefore, you should include a test statement at the top of the file, like this:
test -f program-executed-later-in-file || exit 5 |
If the status command is given, the init script will return the following exit status codes.
| 0 | program is running or service is OK |
| 1 | program is dead and /var/run pid file exists |
| 2 | program is dead and /var/lock lock file exists |
| 3 | program is stopped |
| 4 | program or service status is unknown |
| 5-99 | reserved for future LSB use |
| 100-149 | reserved for distribution use |
| 150-199 | reserved for application use |
| 200-254 | reserved |
In the case of init script commands other than "status" (i.e., "start", "stop", "restart", "reload", and "force-reload"), the init script must return an exit status of zero if the action described by the argument has been successful. Otherwise, the exit status shall be non-zero, as defined below. In addition to straightforward success, the following situations are also to be considered successful:
restarting a service (instead of reloading it) with the "force-reload" argument
running "start" on a service already running
running "stop" on a service already stopped or not running
running "restart" on a service already stopped or not running
In case of an error, while processing any init script action except for "status", the init script must print an error message and return one of the following non-zero exit status codes.
| 1 | generic or unspecified error (current practice) |
| 2 | invalid or excess argument(s) |
| 3 | unimplemented feature (for example, "reload") |
| 4 | user had insufficient privilege |
| 5 | program is not installed |
| 6 | program is not configured |
| 7 | program is not running |
| 8-99 | reserved for future LSB use |
| 100-149 | reserved for distribution use |
| 150-199 | reserved for application use |
| 200-254 | reserved |
All error messages must be printed on standard error. All status messages must be printed on standard output.
Since init files may be run manually by a system administrator with non-standard environment variable values for PATH, USER, LOGNAME, etc. init files must not depend on the values of these environment variables. They should set them to some known/default values if they are needed.