Is there a particular reason you've used system instead of an exec? How do you expect data to get into your child if you never read or print? Do you expect the child to do anything after its child returns? I probably would have written this as (untested for your target): 
    use POSIX qw( mkfifo );

    my $svitok_truby;
    mkfifo( $svitok_truby, 0700 ) || die "Ошиб
+ка создани&#110
+3; трубы  $svitok_truby  : $!";


    my @args = ('/usr/bin/mplayer', '-slave', "-input file=$svitok_tru
+by", '/tmp/1.flac');
    local $SIG{CHLD} = "IGNORE";

    my $pid = fork();
    die "Fork failed\n" unless defined $pid;
    if ($pid == 0) {
        $| = 1;
        exec @args;
    }

    open (my $FIFO, '>', $svitok_truby)  || die "can't open $svitok_tr
+uby: $!";
    while(read STDIN, my($char), 1) {
        print $FIFO $char;
    }
    close($FIFO);

[download]

See also Named Pipes and note loop terminates on ^D.

#11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.

In reply to Re: To organize pipe right way. by kennethk
in thread To organize pipe right way. by nikolay

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