That's a link to sort.pm in the kurila distribution. You want the in the perl distribution: sort

You can specify, which sort method to use for sorting with perl sort function.

The point isn't to use merge sort. The point is to sort files, which merge sort can do. use sort can't help with that.

You can use Tie::File module

I don't think sort can sort tied arrays in-place, so sort would cause the entire file to be loaded into memory.

Even if sort sorts tied arrays in-place, the performance would be abysmal. We're talking about writing out (tens of? hundred of?) thousands of lines O(N log N) times.

Finally, it would use more than "not much" memory. Tie::File keeps an index of every line it has encountered in the file. That usually means, as it does in this case, that it keeps an index of every line in the file. This is in addition to the cache. That's a significant amount of memory in this case, but it sounds like it could be acceptable.

In reply to Re^4: read and sort multiple files (wheel reuse) by ikegami
in thread read and sort multiple files by newPerlr

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.