gistfile1.txt

Rehearsal ----------------------------------------------------
normal SHA-1       3.130000   1.040000   4.170000 (  4.180956)
shell SHA-1        0.010000   0.040000   3.990000 (  4.042143)
file-based SHA-1   3.010000   0.510000   3.520000 (  3.534705)
------------------------------------------ total: 11.680000sec

                       user     system      total        real
normal SHA-1       3.140000   1.040000   4.180000 (  4.196356)
shell SHA-1        0.010000   0.040000   3.990000 (  4.007471)
file-based SHA-1   3.010000   0.520000   3.530000 (  3.544147)

gistfile2.rb

require 'benchmark'
require 'digest/sha1'

name = "big.tar.gz"


Benchmark.bmbm do |x|
  x.report("normal SHA-1") {
    100.times { File.open(name, 'r') { |file| Digest::SHA1.hexdigest(file.read) } }
  }
  x.report("shell SHA-1") {
    100.times { `openssl sha1 #{name}` }
  }
  x.report("file-based SHA-1") {
    100.times { Digest::SHA1.file(name).hexdigest }
  }
end