By default, /etc/inittab species that your system is set to shutdown and reboot the system in
response to a [Ctrl]-[Alt]-[Del] key combination used at the console. If you would like to completely disable this ability, you will need to comment out the following line in /etc/inittab by putting a hash mark (#) in front of it:ca::ctrlaltdel:/sbin/shutdown -t3 -r now Alternatively, you may just want to allow certain non-root users the right to shutdown the system from the console using [Ctrl]-[Alt]-[Del]. You can restrict this privilege to certain users, by taking the following steps: 1. Add a -a option to the /etc/inittab line shown above, so that it reads: ca::ctrlaltdel:/sbin/shutdown -a -t3 -r now The -a ag tells shutdown to look for the /etc/shutdown.allow le, which you will create in the next step. 2. Create a le named shutdown.allow in /etc. The shutdown.allow le should list the usernames of any users who are allowed to shutdown the system using [Ctrl]-[Alt]-[Del].
response to a [Ctrl]-[Alt]-[Del] key combination used at the console. If you would like to completely disable this ability, you will need to comment out the following line in /etc/inittab by putting a hash mark (#) in front of it:ca::ctrlaltdel:/sbin/shutdown -t3 -r now Alternatively, you may just want to allow certain non-root users the right to shutdown the system from the console using [Ctrl]-[Alt]-[Del]. You can restrict this privilege to certain users, by taking the following steps: 1. Add a -a option to the /etc/inittab line shown above, so that it reads: ca::ctrlaltdel:/sbin/shutdown -a -t3 -r now The -a ag tells shutdown to look for the /etc/shutdown.allow le, which you will create in the next step. 2. Create a le named shutdown.allow in /etc. The shutdown.allow le should list the usernames of any users who are allowed to shutdown the system using [Ctrl]-[Alt]-[Del].
The format of the /etc/shutdown.allow le is a list of usernames, one per line, like the following: stephen jack sophie According to this example shutdown.allow le, stephen, jack, and sophie are allowed to shutdown the system from the console using [Ctrl]-[Alt]-[Del]. When that key combination is used, the shutdown -a in /etc/inittab checks to see if any of the users in /etc/shutdown.allow (or root) are logged in on a virtual console. If one of them is, the shutdown of the system will continue; if not, an error message will be written to the system console instead. For more information on shutdown.allow see the shutdown man page.
