Nashirak was pointing out that to find a certain line, the program would have to read everything else before it as well, to find where the lines begin and end.
If the file isn't too vast, you could just go
$file=file('file.txt');
echo $file[4];
If that's too heavy,
$file=fopen('install.txt','r');
for($i=0;$i<5;$i++)
{
$line=fgets($file,1024);
}
echo $line;
fclose($file);
...assuming that no line is more than about 1024 characters long.
