pil=3
for((;$pil!=0;))
{
        echo "Menu"
        echo "1.Sign In"
        echo "2.Sign Up"
        echo "0.Exit"
        echo -n "Pilihan : "
        read pil
        if((pil==1))
        then
                echo -n "Username: "
                read username
                echo -n "Password: "
                read password
                cekuser=`grep $username login.txt`
                cekpassword=`grep -a1 $username login.txt|grep -v $username`
                if(($username==$cekuser && $password==$cekpassword))
                then
                        pilu=3
                        for((;$pilu!=2;))
                        {
                                echo "1.Change Username And Password"
                                echo "2.Sign Out"
                                echo -n "Pilihan: "
                                read pilu
                                if((pilu==1))
                                then
                                        echo -n "New Username: "
                                        read newusername
                                        echo -n "New Password: "
                                        read newpassword
                                        sed -i 's/'$username'/'$newusername'/g' login.txt
                                        sed -i 's/'$cekpassword'/'$newpassword'/g' login.txt
 					 let $username=$newusername
                                        let $cekpassword=$newpassword
                                fi
                        }
                else
                        echo "Username or Password Incorrect"
                fi
        elif((pil==2))
        then
                echo -n "Username: "
                read user
                echo $user >> login.txt
                echo -n "Password: "
                read pass
                echo $pass >> login.txt
        fi
}