Topic awaiting preservation: How do I retrieve the last line of a file?

I go through a file using
WHILE(! feof()), during which
I write to a file ($wfile).

Once done, I need to make a
change in the last line of the output
file.

How do I do this?

If you want to append a new line, you simply open the file in append mode, $fh = fopen($myFile, 'a');
Otherwise, you could load the file with file_get_contents, explode it using a "\n" separator (end of line character), edit the last entry in your array, then write it back.

File access is fast enough so while this is not perfect, it will get the job done.