Need Help with sorting.

[skybux]

I have a text file

! Confirmed
2
@ May Be
S
T
z12
A
Be
Kar
Mash
z
A
AA Waiting Rsvp 144
K
Laj
Man
Nis
Res
She
didi
sister)
A
A
B
C
D
Z need to send Invitex
31
# Unable
A
B
D
S
S
test3
z
I would like
my file to be sorted but.
A
B
D
S
S
test3
! Confirmed
2
@ May Be
S
T
z12
A
Be
Kar
Mash
z
A
AA Waiting Rsvp 144
K
Laj
Man
Nis
Res
She
didi
sister)
A
A
B
C
D
Z need to send Invitex
31
# Unable
-tu

[skybux]

<?php $lines = file("todo.txt"); natsort($lines); file_put_contents("todo.txt", implode("", $lines)); ?>

This the script I use.