The -0 command line option sets $/, the input record separator. The special value -00 sets $/ = ''.

When $/ is set to the null string, like this, it has the effect of using one or more blank lines as the record separator.

However, it still delimits the input records with \n\n. So in effect \n\n+ becomes \n\n. Take for instance the following input file (where $ represents a newline): 

    These are the days.$
    $
    $
    $
    $
    These are the days.$
    $
    $
    $
    These are the days.$

[download]

Filtering it through the following program shows how the records are delimited: 

    #!/usr/bin/perl -00n

    s/\n/\$/g;
    print "<$_>\n";

    __END__
    Prints:
    <These are the days.$$>
    <These are the days.$$>
    <These are the days.>

[download]

Some of this is explained in perlrun and some in perlvar.

--
John.

In reply to Re: command line -00 option by jmcnamara
in thread command line -00 option by silence

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.