Perl or Python looping over a set of file handles would seem like the most i efficient approach. For a more pedestrian solution, an awk script run four times with different parameters might be acceptable even if the file is big.
Does file four only contain every tenth line, and then 11, 14, and 17 go to the first file again?
Code:
perl -MIO::File -ne 'BEGIN { map { $file[$_] = IO::File->new(">file$_") || die $!} 0..3;
@m = (0, 1, 2, 0, 1, 2, 0, 1, 2, 3);
}
$file[$m[$. % 9]]->print || die $!'
