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.\"     @(#)rc.8	8.2 (Berkeley) 12/11/93
.\"
.Dd December 11, 1993
.Dt RC 8
.Os
.Sh NAME
.Nm rc
.Nd command scripts for system startup
.Sh SYNOPSIS
.Nm /etc/rc
.Nm /etc/rc.conf
.Nm /etc/rc.local
.Nm /etc/rc.securelevel
.Nm /etc/netstart
.Nm /etc/rc.shutdown
.Sh DESCRIPTION
.Nm rc
is the command script that is invoked by
.Xr init 8
during an automatic reboot and after single user mode is exited;
it performs system housekeeping chores and starts up system daemons.
As well,
.Nm rc
is intricately tied to the
.Nm netstart
script, which runs commands and daemons pertaining to the network.
The
.Nm rc.securelevel
and
.Nm rc.local
scripts hold commands which are pertinent only to a specific site.
.Pp
All four of these startup scripts are (or can be) controlled to some
extent by variables defined in
.Nm rc.conf ,
which specifies which daemons and services are to be run.
.Pp
When an automatic reboot is in progress,
.Nm rc
is invoked with the argument
.Em autoboot .
The first portion of
.Nm rc
runs an
.Xr fsck 8
with option
.Fl p
to ``preen'' all the disks of minor inconsistencies resulting
from the last system shutdown and to check for serious inconsistencies
caused by hardware or software failure.
If this auto-check and repair succeeds, then the second part of
.Nm rc
is run.
.Pp
The second part of
.Nm rc ,
which is run after an auto-reboot succeeds and also if
.Nm rc
is invoked when a single user shell terminates (see
.Xr init 8 ) ,
then asks
.Nm rc.conf
for configuration variables,
mounts filesystems, starts system daemons,
preserves editor files,
clears the scratch directory
.Pa /tmp ,
and saves any possible core image that might have been
generated as a result of a system crash, with
.Xr savecore 8 .
.Pp
Before
.Nm rc
starts most system daemons,
.Nm netstart
is executed.
.Nm netstart
defines the machine's name, configures various  network interfaces
and system features, initializes the routing table, and numerous
other tasks.
.Pp
.Nm rc.securelevel
is executed by
.Nm rc
to start daemons that must run before the security level changes.
Following this,
.Nm rc
then sets the security level to the values specified in
.Nm rc.conf .
.Pp
.Nm rc.local
is executed towards the end of
.Nm rc
(it is not the very last as there are a few services that must be
the started at the very end).
Normally,
.Nm rc.local
contains commands and daemons that are not part of the
stock installation.
.Pp
.Sh CONFIGURATION EXAMPLES
The
.Nm rc.conf
file contains a series of Bourne-shell syntax assignments that
are used to configure kernel configurations, network configuration,
and various other system daemons.
As described above, this file is sourced (using
.Xr sh 1
of course) by
.Pa /etc/rc .
Various comments in
.Nm rc.conf
make it clear what each variable does.  Refer to the specific man pages
for each daemon to determine what that subsystem does.
.Pp
For example, the 
.Xr sendmail 8
daemon is controlled by the line
.Bd -literal
    sendmail_flags=NO       # for normal use: sendmail_flags="-bd -q30m"
.Ed
.Pp
This does not start
.Xr sendmail 8
at system startup.  But
.Xr sendmail 8
is started with the specified flags if the specification is modified to be
.Bd -literal
    sendmail_flags="-bd -q30m"      # for 'normal' use: sendmail_flags="-bd -q30m"
.Ed
.Pp
.Sh SEE ALSO
.Xr sysctl.conf 5 ,
.Xr init 8 ,
.Xr reboot 8 ,
.Xr savecore 8
.Sh HISTORY
The
.Nm
command appeared in
.Bx 4.0 .