Well, you really need to read line by line to ensure that you are in line X, unless you have fixed line sizes.

Other thing that you can do, to avoid to alwasy read all the file, is to save something like an index of the position in bytes of some lines in an extra file. Soo, for a big file you can have some indexed lines, and when you want to go to line X, you choose the nearest indexed line to start to search for line X, but note that the search for the nearest line in the index need to be very fast and small, or you won't get too much optimization.

Graciliano M. P.
"Creativity is the expression of the liberty".


In reply to Re: Best way to read line x from a file by gmpassos
in thread Best way to read line x from a file by Melly

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":



  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.