trap '' 1 2 3 18  
#trap builtin stops user from terminating script, eg 18 for ctrl-Z
stty -echo  #not to display key typed
echo -n "Key: "
read key_1
echo
echo -n "Again: "
read key_2
echo

key_3=    #create null value for key_3
if [ "$key_1" = "$key_2"  ]
	then
		tput clear  #clear screen
		until [ "$key_3" = "$key_2"  ]
		do
			read key_3
		done
	else
		echo "eg11_locktty: keys do not match"
fi
stty echo #turn on display key typed