#!/bin/bash
#######This script makes sure that the user name that is entered ###############
###### is valid and if NOT it keeps prompting for the user name  ###############
#############################################################################################

# CREATED BY FAHAD SAEED and FAHAD ALI ARSHAD

string=""

cp /home/script/database /home/script/database1

while test $string=""
do 
mylogin=""

#prompts the user for user name and enters this in file named login

zenity --entry --title="LAB 1" --text="Enter the USERNAME">/home/script/login


# thIS will make the database1 to appear in the database2 with every data one line each

sed 's/[ ][ ]*/\
/g' /home/script/database1>/home/script/database2

#now comparing the login entered with the logins in the database

grep -f /home/script/login /home/script/database2>/home/script/test1

#if the login is in the database then test1 should not be empty

string=`cat /home/script/test1`
echo $string

# if the $string is empty it means that the login name entered is not in the database
#else it exits this loop
export $string

if test "$string" = ""
	then
	zenity --error --text="Incorrect user name or password"
	#echo incorrect login name or password
else

	exit 0

fi

# end of while looop
done