I use Algorithm::Diff’s diff/sdiff for this kind of thing. I started to clean up some of my code for an example but I'm really not sure what you think the output file should look like. I only do text diffs for HTML display so I can use things like <span class="added">some</span> <span class="changed">test</span>. I don't know what that looks like without markup or if there is a formalized "diff" markup in *nix other than the >|< or patch output stuff and that doesn't seem appropriate here; and if it is appropriate here, perfectly good tools already exist to generate it.

The approach with the Algorithm::Diff routines would be to turn the files into arrays, either line-wise or word or character; whatever granularity you want.


In reply to Re: comparing any two text files and writing the difference to a third file by Your Mother
in thread comparing any two text files and writing the difference to a third file by balanunni

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.