sub tie_file {
  my @lines;
  tie @lines, 'Tie::File', $file or die "$!";
  map {"$_\n"} @lines[-$limit..-1];
}

##</code><code>##

[chmrr@supox chmrr]$ wc -l /var/log/messages
   4442 /var/log/messages
[chmrr@supox chmrr]$ perl -w tailbm.pl -10 100 /var/log/messages
Benchmark: running f_rb_obj, f_rb_obj_u, f_rb_tie, f_rb_tie_u, file_tail, grinder, lastn, lastn_getc, tie_file, each for at least 10 CPU seconds...
  f_rb_obj: 11 wallclock secs (10.35 usr +  0.22 sys = 10.57 CPU) @ 662.54/s (n=7003)
f_rb_obj_u: 11 wallclock secs (10.54 usr +  0.12 sys = 10.66 CPU) @ 650.19/s (n=6931)
  f_rb_tie: 11 wallclock secs (10.48 usr +  0.20 sys = 10.68 CPU) @ 545.13/s (n=5822)
f_rb_tie_u: 12 wallclock secs (10.39 usr +  0.16 sys = 10.55 CPU) @ 537.25/s (n=5668)
 file_tail: 12 wallclock secs (10.60 usr +  0.14 sys = 10.74 CPU) @ 333.71/s (n=3584)
   grinder: 10 wallclock secs (10.49 usr +  0.07 sys = 10.56 CPU) @ 26.23/s (n=277)
     lastn: 12 wallclock secs ( 7.79 usr +  2.63 sys = 10.42 CPU) @ 26.97/s (n=281)
lastn_getc: 11 wallclock secs ( 8.83 usr +  1.46 sys = 10.29 CPU) @ 28.38/s (n=292)
  tie_file: 11 wallclock secs (10.15 usr +  0.12 sys = 10.27 CPU) @  3.89/s (n=40)

##</code><code>##

[chmrr@supox chmrr]$ perl -w tailbm.pl 500 100 /var/log/messages
Benchmark: timing 500 iterations of backticks, f_rb_obj, f_rb_obj_u, f_rb_tie, f_rb_tie_u, file_tail, grinder, lastn, lastn_getc, tie_file...
 backticks:  1 wallclock secs ( 0.43 usr  0.16 sys +  0.61 cusr  0.30 csys =  1.50 CPU) @ 847.46/s (n=500)
  f_rb_obj:  1 wallclock secs ( 0.71 usr +  0.04 sys =  0.75 CPU) @ 666.67/s (n=500)
f_rb_obj_u:  1 wallclock secs ( 0.77 usr +  0.00 sys =  0.77 CPU) @ 649.35/s (n=500)
  f_rb_tie:  1 wallclock secs ( 0.89 usr +  0.02 sys =  0.91 CPU) @ 549.45/s (n=500)
f_rb_tie_u:  1 wallclock secs ( 0.91 usr +  0.02 sys =  0.93 CPU) @ 537.63/s (n=500)
 file_tail:  1 wallclock secs ( 1.47 usr +  0.01 sys =  1.48 CPU) @ 337.84/s (n=500)
   grinder: 19 wallclock secs (18.93 usr +  0.22 sys = 19.15 CPU) @ 26.11/s (n=500)
     lastn: 19 wallclock secs (14.20 usr +  4.34 sys = 18.54 CPU) @ 26.97/s (n=500)
lastn_getc: 20 wallclock secs (15.09 usr +  2.64 sys = 17.73 CPU) @ 28.20/s (n=500)
  tie_file: 143 wallclock secs (126.62 usr +  1.81 sys = 128.43 CPU) @  3.89/s (n=500)