How to read a text file with variable line length?

Hello all, I would like to ask the following help concerning text files. I've got column delimited text files and I need to read each line/record to populate a MySQL table. I understand that when you use fread($file, $length) you must specify the length of each line. The problem is that the last column is a description column and it can be from zero chars to 50 chars long. Because of that the length of each line is not a fixed number. What to do in a situation like this? Thanks in advance, Carlos Fernando Scheidecker Antunes.