There is a fast way to seek to desired line and read given number of lines. It involves a pre-step. The basic idea is as follows:

Pre-step (once only initialization step)
Build an array of line offsets, @offset, as you loop through the file on the first pass. So $offset[120] is the byte offset of the 121st line in the file (zero based array index).
my $curpos = 0;
my @offset;
$offset[0] = 0;  # 1st line always start at pos 0
while (<$fh>) {
  $offset[++$curpos] = tell $fh;
}

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Fast-read (repeatedly called)
Seek to the byte offset for the desired start line, with a single seek - 
seek $fh, $offset[$cur], 0;

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Read the next $row - $cur + 1 number of lines

In reply to Re: Fast way to read from file by Roger
in thread Fast way to read from file by Hena

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