Will the same file be read over and over again? If so then it can become worth-while to create an index of where the beginnings of lines are, by reading lines and using ftell() to determine the current position, storing that value, reading more lines, and so on. Once you have the index generated once, you can use it to fseek() to somewhere at or before the target row and then just read that row.
This indexing process does require reading the file through once, but it avoids having to read it from the beginning each time.
None of the operating systems that MATLAB runs on support positioning directly to a particular line in a text file (not unless the lines are all exactly the same length.)
