...which uses the 'diamond operator'. Normally, the diamond operator takes all the file names specified on the command line as arguments, combines the corresponding files into one big file, and then assigns a line from the big file to $_ each time through the loop. However, if you do not specify any file names as arguments on the command line, then the diamond operator reads from STDIN. Presumably, that is what you did, so your program is waiting for you to type in a line of text for the diamond operator to process (you would hit ctrl+D to signal end-of-file after typing in all your lines).

Also, when you specify filenames as arguments on the command line, if you specify a file name as: -, then the diamond operator will read from STDIN for that portion of the big file.

In reply to Re^2: -p option with __DATA__ by 7stud
in thread -p option with __DATA__ by jdalbec

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.