File handling

I'm opening a flat file database for reading:

$file="base.dat";
$fp=fopen($file,"r");
$body=fread($fp,filesize($file));
fclose($fp);

How should I modify the code in order to read the first entry on the last line and add 1, i.e. if file contains:

|1|Jack
|2|Bob

I would like to return 2 and add one = 3

I'm a newbie to php, completely blank...

You need to work with FILE() if you want to read line by line. Here is an example.. note is pretty ugly code but it will return the last number + 1

$lines = file("read.txt");
$subarray = explode("|",$lines[count($lines) -1]);
$subarray[1]++;
echo($subarray[1]);