capture ctrl+c

procfs · 11-16-2006, 12:11 AM

Hi

I have some scripts that will show me a backup options (Menu),

At the menu if some one press ctrl + c it exit and gives the prompt. I want to stop this.

if some one press ctrl + c I want to logout from the system. How ca I do this.

I am using Redhat ES3 update 8

Thank you

Regards

Asanka

Quigi · 11-16-2006, 07:37 AM

I'm not sure I understand what you're trying to do.
Maybe that "someone" should exec your script from the login shell?

OTOH, you mention you have "scripts" -- what scripting language? (E.g., bash, perl, tcl, ...) If it's bash, and you want to do something specific in response to ctrl+c, and ,

see man bash, particularly the trap builtin. You'll want SIGINT as the sigspec.

You need to tell us more.

procfs · 11-17-2006, 05:54 AM

Hi Quigi

There are some bash shell scripts that I use to backup my databases.

Thing is while the user is in the menu if he press control c he will be taken to the shell prompt. I want to stope this I wan is if the user press Control C he must be logged out.

Is there a way to do this.

Thanks

Regards

Asanka

bigearsbilly · 11-17-2006, 08:46 AM

exec your_script

Quigi · 11-17-2006, 08:47 AM

Quote:

Originally Posted by asankacgl

Here are some bash shell scripts that I use to backup my databases.

I want to stope this I wan is if the user press Control C he must be logged out.

(emphasis mine)

Please explain what you're trying to achieve. Who is the user? Not you? Somebody that walks up to your terminal while you are using some bash shell scripts, and hits C-c to gain access to your shell?

Quote:

Is there a way to do this.

Yes.

matthewg42 · 11-17-2006, 09:23 AM

In a bash script, you can trap a signal and handle it with a function. When ^C is pressed in a terminal, the SIGINT signal is sent to the shell, so we can trap this. bash also sets an environment variable PPID which is the PID of the parent process, so you can send a signal to this in your signal handler. SIGHUP would be a good one, requesting that the tty hang up.

In this script you can use ^C to kill the parent shell. The while loop is just an annoying example menu which never exits.

Code:

#!/bin/bash

kill_parent () {
    echo 'death to my parent!'
    sleep 3
    kill -HUP $PPID
}

trap kill_parent INT

while true; do
    echo "Options:"
    echo "1. Say hi"
    echo "2. Say lo"
    echo "3. Say hi ho"
    echo -n "your choice? > "
    read answer
    case $answer in
    1)
        echo "hi"
        ;;
    2)
        echo "lo"
        ;;
    3)
        echo "hi ho"
        ;;
    *)
        echo "what?"
        ;;
    esac
done

procfs · 11-17-2006, 08:56 PM

Hay gus thank you for your help

Hay I was able to do this by using some thing like

trap 'echo "Control-C disabled."' 2

Best regards

Asanka