Linux Disable the Ctrl-Alt-Delete shutdown keys

by on May 24, 2006 · 3 comments· LAST UPDATED September 13, 2007

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On a production system it is recommended that you disable the [Ctrl]-[Alt]-[Delete] shutdown. 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.

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

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{ 3 comments… read them below or add one }

1 chika September 20, 2011 at 7:55 pm

file:///etc/inittab doesn’t exist on my Lucid


2 Marius Gedminas January 23, 2012 at 10:57 am

Ubuntu switched from SysV init to upstart a while ago. /etc/inittab is gone; Ctrl+Alt+Del is handled by /etc/init/control-alt-delete.conf.


3 chika.tambun January 25, 2012 at 10:51 am

yes, it worked
btw, thanks for replying


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