Check he or she is login

check he or she is login or not the user after every 1 minute

The UNIX operating system is a set of programs that act as a link between the computer and the user. The computer programs that allocate the system resources and coordinate all the details of the computer’s internals is called the operating system or kernel. Users communicate with the kernel through a program known as the shell. The shell is a command line interpreter; it translates commands entered by the user and converts them into a language that is understood by the kernel.

We know UNIX is a computer Operating System which is capable of handling activities from multiple users at the same time. If this system is used by multiple user and we want to check that a user is login or not or in every minute then that question is good to do because the question is mine.
So let’s code

#!/bin/bash
read -p "Enter the name of your friend: " name
ch=`who | grep "$name"`
until [ -z ch ]; do
sleep 1s
echo "Waiting..."
done

For more Linux questiom

Output will be:

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