may be used to change the system runlevel.
argument should be one of the multi-user runlevels
to halt the system,
to reboot the system or
to bring the system down into single-user mode.
Normally you would use the
tool to halt or reboot the system, or to bring it down to single-user mode.
may also be
S or s
which will place the system directly into single-user mode without actually
stopping processes first, you probably won't want that.
The runlevel is changed by emitting the
event, which includes the new runlevel in the
environment variable as well as the previous runlevel (obtained from the
environment or from
will write the new runlevel to
and append a new entry to
may be also used to send basic commands to the
daemon for compatibility with System V. These are:
Q or q
to request that
reload its configuration. This is rarely necessary since Upstart watches
its configuration with
and is deprecated by the
U or u
to request that the
daemon re-execute itself. This is not recommended since Upstart is currently
unable to preserve its state, but is necessary when upgrading system
This specifies an additional environment variable to be included in the event
will read the current runlevel from this environment variable if set in
preference to reading from
Where the current runlevel will be read from; this file will also be updated
with the new runlevel.
A new runlevel record will be appended to this file for the new runlevel.
daemon does not keep track of runlevels itself, instead they are implemented
entirely by its userspace tools.