rcS(5) Debian Administrator's Manual rcS(5)NAME
rcS - variables that affect the behavior of boot scripts
DESCRIPTION
The /etc/default/rcS file contains variable settings in POSIX format:
VAR=VAL
Only one assignment is allowed per line. Comments (starting with '#') are also allowed.
OPTIONS
The following variables can be set. For the default values please see /usr/share/initscripts/default.rcS.
TMPTIME
On boot the files in /tmp will be deleted if their modification time is more than TMPTIME days ago. A value of 0 means that files
are removed regardless of age. If you don't want the system to clean /tmp then set TMPTIME to a negative value (e.g., -1) or to the
word infinite.
SULOGIN
Setting this to yes causes init to spawn a sulogin on the console early in the boot process. If the administrator does not login
then the sulogin session will time out after 30 seconds and the boot process will continue.
DELAYLOGIN
Normally the system will not let non-root users log in until the boot process is complete and the system has finished switching to
the default runlevel (usually level 2). However, in theory it is safe to log in a bit earlier, namely, as soon as inetd has
started. Setting the variable to no allows earlier login; setting the variable to yes prevents it.
Some details: The DELAYLOGIN variable controls whether or not the file /var/lib/initscripts/nologin is created during the boot
process and deleted at the end of it. /etc/nologin is normally a symbolic link to the latter location, and the login(1) program
refuses to allow non-root logins so long as (the target of) /etc/nologin exists. If you set the variable to no then it is advisable
to ensure that /var/lib/initscripts/nologin does not exist.
UTC This is used to govern how the hardware real time clock is interpreted when it is read (e.g., at boot time, for the purpose of set-
ting the system clock) and when it is written (e.g., at shutdown). If this option is set to no then the system clock is assumed to
be set to local time. If the option is set to yes then the system clock is assumed to be set to something approximating Coordinated
Universal Time (UTC). (POSIX systems keep a variant of UTC, without leap seconds.)
On contemporary Debian systems (although change has been requested at http://bugs.debian.org/346342), if UTC is set to no then
/usr/share/zoneinfo must be readable early in the boot process. If you want to keep /usr on a separate filesystem then you must
still ensure that the target of /etc/localtime points to the correct zone information file for the time zone of the time kept in
your hardware real time clock.
VERBOSE
Setting this option to no (in lower case) will make the boot process a bit less verbose. Setting this option to yes will make the
boot process a bit more verbose.
FSCKFIX
When the root and all other file systems are checked, fsck is invoked with the -a option which means "autorepair". If there are
major inconsistencies then the fsck process will bail out. The system will print a message asking the administrator to repair the
file system manually and will present a root shell prompt (actually a sulogin prompt) on the console. Setting this option to yes
causes the fsck commands to be run with the -y option instead of the -a option. This will tell fsck always to repair the file sys-
tems without asking for permission.
NOTE
The EDITMOTD and RAMRUN variables are no longer used.
AUTHOR
Miquel van Smoorenburg <miquels@cistron.nl>
SEE ALSO inetd(8), init(8), inittab(5), login(1).
16 Jan 2006 rcS(5)
Check Out this Related Man Page
SHUTDOWN(8) Linux System Administrator's Manual SHUTDOWN(8)NAME
shutdown - bring the system down
SYNOPSIS
/sbin/shutdown [-t sec] [-arkhncfF] time [warning-message]
DESCRIPTION
shutdown brings the system down in a secure way. All logged-in users are notified that the system is going down, and login(1) is blocked.
It is possible to shut the system down immediately or after a specified delay. All processes are first notified that the system is going
down by the signal SIGTERM. This gives programs like vi(1) the time to save the file being edited, mail and news processing programs a
chance to exit cleanly, etc. shutdown does its job by signalling the init process, asking it to change the runlevel. Runlevel 0 is used
to halt the system, runlevel 6 is used to reboot the system, and runlevel 1 is used to put to system into a state where administrative
tasks can be performed; this is the default if neither the -h or -r flag is given to shutdown. To see which actions are taken on halt or
reboot see the appropriate entries for these runlevels in the file /etc/inittab.
OPTIONS -a Use /etc/shutdown.allow.
-t sec Tell init(8) to wait sec seconds between sending processes the warning and the kill signal, before changing to another runlevel.
-k Don't really shutdown; only send the warning messages to everybody.
-r Reboot after shutdown.
-h Halt after shutdown.
-n [DEPRECATED] Don't call init(8) to do the shutdown but do it ourself. The use of this option is discouraged, and its results are
not always what you'd expect.
-f Skip fsck on reboot.
-F Force fsck on reboot.
-c Cancel an already running shutdown. With this option it is of course not possible to give the time argument, but you can enter a
explanatory message on the command line that will be sent to all users.
time When to shutdown.
warning-message
Message to send to all users.
The time argument can have different formats. First, it can be an absolute time in the format hh:mm, in which hh is the hour (1 or 2 dig-
its) and mm is the minute of the hour (in two digits). Second, it can be in the format +m, in which m is the number of minutes to wait.
The word now is an alias for +0.
If shutdown is called with a delay, it creates the advisory file /etc/nologin which causes programs such as login(1) to not allow new user
logins. Shutdown removes this file if it is stopped before it can signal init (i.e. it is cancelled or something goes wrong). It also
removes it before calling init to change the runlevel.
The -f flag means `reboot fast'. This only creates an advisory file /fastboot which can be tested by the system when it comes up again.
The boot rc file can test if this file is present, and decide not to run fsck(1) since the system has been shut down in the proper way.
After that, the boot process should remove /fastboot.
The -F flag means `force fsck'. This only creates an advisory file /forcefsck which can be tested by the system when it comes up again.
The boot rc file can test if this file is present, and decide to run fsck(1) with a special `force' flag so that even properly unmounted
filesystems get checked. After that, the boot process should remove /forcefsck.
The -n flag causes shutdown not to call init, but to kill all running processes itself. shutdown will then turn off quota, accounting, and
swapping and unmount all filesystems.
ACCESS CONTROL
shutdown can be called from init(8) when the magic keys CTRL-ALT-DEL are pressed, by creating an appropriate entry in /etc/inittab. This
means that everyone who has physical access to the console keyboard can shut the system down. To prevent this, shutdown can check to see if
an authorized user is logged in on one of the virtual consoles. If shutdown is called with the -a argument (add this to the invocation of
shutdown in /etc/inittab), it checks to see if the file /etc/shutdown.allow is present. It then compares the login names in that file with
the list of people that are logged in on a virtual console (from /var/run/utmp). Only if one of those authorized users or root is logged
in, it will proceed. Otherwise it will write the message
shutdown: no authorized users logged in
to the (physical) system console. The format of /etc/shutdown.allow is one user name per line. Empty lines and comment lines (prefixed by a
#) are allowed. Currently there is a limit of 32 users in this file.
Note that if /etc/shutdown.allow is not present, the -a argument is ignored.
FILES
/fastboot
/etc/inittab
/etc/init.d/halt
/etc/init.d/reboot
/etc/shutdown.allow
NOTES
A lot of users forget to give the time argument and are then puzzled by the error message shutdown produces. The time argument is manda-
tory; in 90 percent of all cases this argument will be the word now.
Init can only capture CTRL-ALT-DEL and start shutdown in console mode. If the system is running the X window System, the X server pro-
cesses all key strokes. Some X11 environments make it possible to capture CTRL-ALT-DEL, but what exactly is done with that event depends on
that environment.
Shutdown wasn't designed to be run setuid. /etc/shutdown.allow is not used to find out who is executing shutdown, it ONLY checks who is
currently logged in on (one of the) console(s).
AUTHOR
Miquel van Smoorenburg, miquels@cistron.nl
SEE ALSO fsck(8), init(8), halt(8), poweroff(8), reboot(8)
Juli 31, 2001 SHUTDOWN(8)