Benchmark: timing 1000 iterations of filereadbackwards, tailz, tailz1... filereadbackwards: 1612.90/s (n=1000) tailz: 152.91/s (n=1000) tailz1: 12500.00/s (n=1000) #### #!/usr/bin/perl use Benchmark; use File::ReadBackwards; use strict; #open (BLACKHOLE,">/dev/null") or die $!; my $numlines =10; my $filename = 'ARCHIVES'; timethese(1000, { #################################################### filereadbackwards => sub { my @lines; my $line; my $count=0; my $bw = File::ReadBackwards->new($filename) or die "can't read filename $!" ; while(defined($line = $bw->readline)){ push @lines,$line ; last if ++$count >= $numlines; } @lines= reverse @lines; # print BLACKHOLE "@lines\n"; }, ##################################################### tailz => sub { my $byte; open FILE, "<$filename" or die "Couldn't open filename: $!"; seek FILE,-1, 2; #get past last eol my $count=0; while (1){ seek FILE,-1,1; read FILE,$byte,1; if(ord($byte) == 10 ){$count++;if($count == 10){last}} seek FILE,-1,1; if (tell FILE == 0){last} } $/=undef; my $tail = ; # print BLACKHOLE "$tail\n"; }, ######################################################### tailz1 => sub { my $chunk = 400 * $numlines; #assume a <= 400 char line(generous) # Open the file in read mode open FILE, "<$filename" or die "Couldn't open $filename: $!"; my $filesize = -s FILE; if($chunk >= $filesize){$chunk = $filesize} seek FILE,-$chunk,2; #get last chunk of bytes my @tail = ; if($numlines >= $#tail +1){$numlines = $#tail +1} splice @tail, 0, @tail - $numlines; # print BLACKHOLE "@tail\n"; }, }); #### #!/usr/bin/perl -w # example for files with max line lengths < 400, but it's adjustable # usage tailz filename numberoflines use strict; die "Usage: $0 file numlines\n" unless @ARGV == 2; my ($filename, $numlines) = @ARGV; my $chunk = 400 * $numlines; #assume a <= 400 char line(generous) # Open the file in read mode open FILE, "<$filename" or die "Couldn't open $filename: $!"; my $filesize = -s FILE; if($chunk >= $filesize){$chunk = $filesize} seek FILE,-$chunk,2; #get last chunk of bytes my @tail = ; if($numlines >= $#tail +1){$numlines = $#tail +1} splice @tail, 0, @tail - $numlines; print "@tail\n"; exit;