Get info out a .dat file

[Anon]

I made a PHP scipt that saves his info in a .dat file with the username as name.
Now i want, to create a login, to get the first rule of the .dat file as variable $user.

i made this already:

$file=fopen("members/$username.dat","r");
...
fclose($file)

What has to be on the place of the dots?
Thanx

[Anon]

$file = file("members/$username.dat","r");

This will put every new line into an array.

Example: $file["0"] is line 1.

[ John Barker