Thank you, haukex, for the information about the correct use of the branch reset, and sorry for making you guess my incorrect code. It was (and is) a bit of a moot point, since I've been given multiple perl solutions to my problem; however, for the record, my aforementioned failed attempt was to combine the ideas I had for what in my original post I described as the former and latter cases: 

perl -0pe 's/(.*?\n*?([^ \n].*?)\n\n.*|.*?\n([^ \n].*?)\n\n.*)/$1/gs' 
+file.txt

[download]

This simply returned the whole file, and I thought it had something to do with the nested parentheses altering what $1 refers to. When I rewrite it correctly, as per haukex's helpful advice: 

perl -0pe 's/(?|.*?\n*?([^ \n].*?)\n\n.*|.*?\n([^ \n].*?)\n\n.*)/$1/gs
+' file.txt

[download]

it does return something, but that something is the desired output only in the case where the first line is non-indented. The reason, obviously, is that I was making a stupid mistake: the first alternative returns a match whether or not the first line of file.txt is indented, so that code is never going to return the output of: 

perl -0pe 's/.*?\n([^ \n].*?)\n\n.*/$1/gs' file.txt

[download]

As I said, it's a moot point, but I thought this follow-up was worth mentioning in case someone who lands on this page learns from my stupid mistake.

Regards,

Maneesh

In reply to Re^3: matching first paragraph satisfying condition by mnshptl32
in thread matching first paragraph satisfying condition by mnshptl32

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.