Considering i have a 100GB txt file containing millions of lines of text. How could i read this text file by block of lines using PHP? 

i can't use `file_get_contents();` because the file is too large. `fgets()` also read the text line by line which will likely takes longer time to finish reading the whole file.

If i'll be using `fread($fp,5030)` wherein '5030' is some length value for which it has to read. Would there be a case where it won't read the whole line(such as stop at the middle of the line) because it has reached the max length?