You still have not told us what you are supposed to do with the stuff you read in??  You can read a file line by line and print out each line as you go and the maximum amount of memory used will be one line's worth.   However, if you are supposed to store all the lines in an array, then you will read the whole file into memory.

> Thanks guys for your helpful comments. I will be more
> descriptive. I am an intern and my mentor wants me to
> use the IO.pos to read the characters of the file
> until the character reaches the ">" symbol.

What problems is that giving you?  You can create a loop, read the character at pos(i), then increment i, and do what Jess Gabriel y Galn suggested.