#!/usr/bin/perl -w
                                                                                
# Strict
use strict;
use warnings;
                                                                                
# User-defined
my $n    = 3;                   # How many lines to read from the end
my $file = "/usr/dict/words";   # File to read
                                                                                
                                                                                
# Main program
my $plines = last_n_lines($file, $n, 256);
print "Last $n line(s) from '$file':\n";
for (my $i = 0; $i < @$plines; $i++) {
    printf " %2d.  '%s'\n", $i+1, $plines->[$i];
}
                                                                                
                                                                                
#
#  In:  $1 ... name of file
#       $2 ... number of lines to read
#       $3 ... (optional) maximum line length
#
# Out:  $1 ... pointer to list of the last N lines from the file.
#
sub last_n_lines {
    my ($fname, $nlines, $maxlen) = @_;
                                                                                
    # Open the file
    open(my $fh, "<", $file) or die "Error -- failed to read '$fname' ($!)\n";
                                                                                
    # Calculate offset near end of file
    $maxlen ||= 1024;
    my $offset = (-s $file) - ($maxlen + 1) * $nlines;
    ($offset > 0) and seek($fh, $offset, 0);
                                                                                
    # Read lines
    my @lines;
    while (!eof($fh)) {
        chomp(my $line = <$fh>);
        push @lines, $line;
    }
                                                                                
    # Return last N
    close $fh;
    splice(@lines, 0, -$nlines);
    return \@lines;
}