I am using IPC::Open3 to communicate with `tar' and am having a problem that I think is related to buffered IO. Here is some sample code: 
    my $command = "tar --tape-length $TAPE_LENGTH -cf $destination $so
+urce";
    my ( $input, $output );
    open3( $input, $output, '', $command );

    while ( my $line = <$output> ) {
        print "from tar: '$line'\n";
        if ( $line =~ m/Prepare volume/ ) {
            # need to change tapes
            ...
        }
    }

[download]
The output I am looking for will be something like this: "Prepare volume #2 for `output' and hit return:". Notice the lack of \n. Is there a way to flush the output on a character by character basis, and then an elegant way of reassembling it so I can use a regex? Or, am I asking the wrong question?

Thanks in advance.

In reply to open* and buffered program output by narse

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.