/usr/share/doc/ruby1.8-examples/examples/sieve.rb is in ruby1.8-examples 1.8.7.352-2ubuntu1.6.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | # sieve of Eratosthenes
max = Integer(ARGV.shift || 100)
sieve = []
for i in 2 .. max
sieve[i] = i
end
for i in 2 .. Math.sqrt(max)
next unless sieve[i]
(i*i).step(max, i) do |j|
sieve[j] = nil
end
end
puts sieve.compact.join(", ")
|