Reading in text file characters

The following code reads in a text file one line at a time. for ($k=0; $k<=count($readfile)-1; $k++) { $fields = split("\t",$readfile[$k]); echo nl2br("$fields[0]<br>"); } The problem is that it seems to strip the empty spaces out. My text file is formatted by lengths. I need to read the first 25 characters from the text file. Then read 50 more... And so on. Can anyone give my the code for reading in a certain number of characters from a text file. Thank you in advance.