Would "foobar" be "\S{3} not preceded by 'bar'"? Is that what you are trying to find?

Yes it would. I thought this much was clear.

I see now the wording of (?!pattern) is what confused me

If you are looking for a "bar" that isn't preceded by a "foo", /(?!foo)bar/ will not do what you want. That's because the (?!foo) is just saying that the next thing cannot be "foo" -- and it's not, it's a "bar", so "foobar" will match. Use look-behind instead (see below).

And I'm certain now, that I only tried s/((?!bar)\S{3,})/\U$1/g ; without \b

In reply to Re^2: To find, this not preceded by that, use (?<!pattern)(?!pattern) (or not) by Anonymous Monk
in thread To find, this not preceded by that, use negative look-behind with negative look-ahead , use (?<!pattern) with (?!pattern), (?<!pattern)(?!pattern) by Anonymous Monk

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.