B::Deparse can shed some light . . . 

$ perl -MO=Deparse,-p -e '$one_line =~ !/^#+/'
($one_line =~ (not /^#+/));

[download]

So what you were really doing was first matching /^#+/ against $_, taking the logical not of what that returned and then attempting to use the string version of that as a regexp to match against $one_line.

Update: And to further explain, that meant you were always splitting and hence would sometimes get lines without all the fields you expected and those would be undefined.

In reply to Re: Re: Re: Help with recurring "uninitialized variable" problem. by Fletch
in thread Help with recurring "uninitialized variable" problem. by C_T

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.