This subroutine takes a file name and a line count (N) and will return an open filehandle with its read pointer set to N lines before the end of the file. This differs from implementations (like that in PPT) because the entire file is not read -- it reads backwards from the end. It's a quickie so there's no buffering as in GNU's tail(1), but that can easily be remedied. Sample usage: 
my $g=lastn("/usr/dict/words", 400);
print while(<$g>);

[download]
It was coded to grab the last few bits of a gigantic logfile we use here and may not be suitable for your needs. Enjoy.
sub lastn {
        my($file, $lines)=@_;
        my $fh;
        $lines++;
        if (! open($fh, $file) ) {
                print "Can't open $file: $!<P/>";
                return;
        }
        binmode($fh);
        sysseek($fh, 0, 2);  # Seek to end
        my $nlcount=0;
        while($nlcount<$lines) {
                last unless sysseek($fh, -1, 1);
                sysread($fh, $_, 1, 0) || die;
                $nlcount++ if ( $_ eq "\n");
                last if $nlcount==$lines;
                last unless (sysseek($fh, -1, 1));
        }
        seek($fh, sysseek($fh, 0, 1), 0) || warn;
        $fh;
}

[download]

In reply to Last N lines from file (tail) by clintp

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