Using a variable is even required if you want to add error checking. 

while (my $line = <DATA>) {

    if ( $. % 10 == 1 ) {
        print $line;
    }

    for (0 .. 3) {
        defined( my $important_line = <DATA> )
            or die("Premature EOF\n");

        print $important_line;
    }
}

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In reply to Re^4: Hmmm: while(), file handle and $_ gotcha by ikegami
in thread Hmmm: while(), file handle and $_ gotcha by roboticus

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