Not a one-liner.

You need to partition all files by size. Then for each size, if there are exactly two files, compare their contents and possibly delete one. If there are more than two files, you have to partition the files of the current size by their fingerprint (CRC, MD5, SHA1, whatever); and for each partition compare-and-possibly-delete-one between all pairs (each partition possibly shrinking as you go, and thus candidate comparisons may be cancelled before they are performed).

This, first of all, is safe. No file is mistakenly deleted because a deletion always follows a full content compare. We don't trust the fingerprint function, but rather use it as an indication that something is supicious. Then, it is reasonably efficient. No comparisons are made if they are bound to fail.

If this were a litte smaller, we *might* have been able to get away with reading a block of each file simultaneously. But as it is we'll run out of file handles first thing :)

In reply to Re: Removing Duplicate Files by gaal
in thread Removing Duplicate Files by tomazos

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.