Halt - Linux Man Page

NAME

halt, reboot, poweroff - stop the system.

SYNOPSIS

/sbin/halt [-n] [-w] [-d] [-f] [-i] [-p] [-h]
/sbin/reboot [-n] [-w] [-d] [-f] [-i]
/sbin/poweroff [-n] [-w] [-d] [-f] [-i] [-h]

DESCRIPTION

Halt notes that the system is being brought down in the file /var/log/wtmp, and then either tells the kernel to halt, reboot or poweroff the system.

If halt or reboot is called when the system is not in runlevel 0 or 6, in other words when it's running normally, shutdown will be invoked instead (with the -h or -r flag). For more info see the shutdown(8) manpage.

The rest of this manpage describes the behaviour in runlevels 0 and 6, that is when the systems shutdown scripts are being run.

OPTIONS

-n

Don't sync before reboot or halt.

-w

Don't actually reboot or halt but only write the wtmp record (in the /var/log/wtmp file).

-d

Don't write the wtmp record. The -n flag implies -d.

-f

Force halt or reboot, don't call shutdown(8).

-i

Shut down all network interfaces just before halt or reboot.

-h

Put all harddrives on the system in standby mode just before halt or poweroff.

-p

When halting the system, do a poweroff. This is the default when halt is called as poweroff.

DIAGNOSTICS

If you're not the superuser, you will get the message `must be superuser'.

NOTES

Under older sysvinit releases , reboot and halt should never be called directly. From release 2.74 on halt and reboot invoke shutdown (8) if the system is not in runlevel 0 or 6. This means that if halt or reboot cannot find out the current runlevel (for example, when /var/run/utmp hasn't been initialized correctly) shutdown will be called, which might not be what you want. Use the -f flag if you want to do a hard halt or reboot.

The -h flag puts all harddisks in standby mode just before halt or poweroff. Right now this is only implemented for IDE drives. A side effect of putting the drive in standby mode is that the write cache on the disk is flushed. This is important for IDE drives, since the kernel doesn't flush the write-cache itself before poweroff.

The halt program uses /proc/ide/hd* to find all IDE disk devices, which means that /proc needs to be mounted when halt or poweroff is called or the -h switch will do nothing.

SEE ALSO

shutdown(8), init(8)

Disable the Ctrl-Alt-Delete shutdown keys

For people who have recently migrated from MS boxes to Nix ones have a habit of using Ctrl+Alt+Del keys for popping up Task Manager or to simply lock the workstation but using that combination on Linux box is hazardous as it shuts down the machine.

So I recommend on disabling Ctrl+Alt+Del keys on your workstation, even on production systems it is recommended that you disable it

It is configured using /etc/inittab (used by sysv-compatible init process) file. The inittab file describes which processes are started at bootup and during normal operation. You need to open this file and remove (or comment it) ctrlaltdel entry.

Ctrlaltdel specifies the process that will be executed when init receives the SIGINT signal. SIGINT is the symbolic name for the signal thrown by computer programs when a user wishes to interrupt the process, for example reboot/shutdown system using [Ctrl]-[Alt]-[Del].). This means that someone on the system console has pressed the CTRL-ALT-DEL key combination. Typically one wants to execute some sort of shutdown either to get into single-user level or to reboot the machine.

How-To disable Ctrl+Alt+Del Keys:

Open /etc/inittab file, enter:
# vi /etc/inittab

Search for line that read as follows:
ca:12345:ctrlaltdel:/sbin/shutdown -t1 -a -r now

And remove the line or comment out the above line by putting a hash mark (#) in front of it:
# ca:12345:ctrlaltdel:/sbin/shutdown -t1 -a -r now

Save the file and exit to shell promot. Reboot system to take effect or type command:
# init q

Trim 1.0 - Removes a number of lines from the beginning of a file

Good utility for people who are not much into scripting.

Excerpts form MANUAL:

Utility used to monitor and control the sizes of (log) files. Examines a text file to see if its length has exceeded a certain limit; if it has, Trim removes a certain number of lines from the beginning of the file. Ideal for use in crontab.

Download source - trim-1.0.tar.gz [4 kb]

Secret Maryo Chronicles 1.8

The Super Mario-inspired platforming game Secret Maryo Chronicles is now at version 1.8 with improved moving platforms and updated sprites.

Screenshots: [ View ] Download: [ secretmaryo.org ]