Contributed by Anonymous Monk on Jan 03, 2001 at 22:16 UTC
Q&A  > files


Some operating systems can optimize file creation (especially for fixed binary record type files) if the file is pre-extended to desired size. This eliminates multiple file extension requests and can produce less fragmented files systems on multi-user systems.

Any tricks to indicate desired size of file during open?

Answer: How do I pre-extend a file to a specified size
contributed by merlyn

seek HANDLE, 0, $desired_size -1; print HANDLE "\0"; seek HANDLE, 0, 0;
Answer: How do I pre-extend a file to a specified size
contributed by abhishek_akj

open FILEHANDLE, " +< filename" or die "Unable to open: $! \n"; truncate FILEHANDLE, $desired_length or print "Unable to truncate: $ +! \n";
truncate just sets the filesize of the file opened by handle to whatever you specify; you can use it to remove characters from file as well as increase the filesize.

Please (register and) log in if you wish to add an answer

  • 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, 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, 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.