I assume that your real problem is that you want to traverse a large log file fast? There are certainly some CPAN module which do this -- and someone will post about it and make this look primitive. :-)

You could try a binary search with seek() to look for the general area to start looking. Something like:

# Find a good place to start traversing a large
# file for sorted data.

return 0 if $filelen < 2000000;  # A few MB? Please... :-)
my $safe_offset = 0;
my $jump = 0.5;
my $step = 0.25;
for(1..8) {
  # See if 
  my($testoff) = int($filelen * $jump);
  seek(FILE, $testoff, 0);

  if ( do_test(*FILE, $threshold) ) {
    $safe_offset = $testoff; # Point to offset for 
    $jump = $jump + $step;
  } else {
    $jump = $jump - $step;
  }
  $step = $step / 2.0;
}

# Go to selected place:
seek(FILE, $safe_offset);
<FILE> if $safe_offset > 0;

return $safe_offset;

sub do_test {
  my(*FILE, $compare) = @_;
  # Has moved somewhere in file. Skip partial line of log:
  <FILE>;
  my $log = <FILE>;
  # You write this (you know the format). Return true if OK:
  return date_test($log, $compare);
}

[download]

Just an idea, ignore if my assumption about your problem was wrong. Code is untested since I'm busy. I'll be back in about a work day and can write more then, if you need more details.

I hope this won't embarrass me when I get back. (-: On the other hand -- I'll make someone's day when they get to point out errors. :-)

Update: Added return stuff, so it sets up offset to file correctly.

In reply to Re: print log file by BerntB
in thread print log file by xiaoyafeng

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