this is a simple script to generate checksums and find ones that start with zeros. when a matching checksum is found, it outputs it and looks for the a checksum with one more zero.

bitcoin_mining_example.rb

# this is a simple script to generate checksums and
# find ones that start with zeros. when a matching
# checksum is found, it outputs it and looks for
# the a checksum with one more zero.

# you can see in the output below that it took only
# 9 tries to find a checksum with one zero, and it
# took 6132845 tries to find one with six zeros.

# example output:
# 9       0ade7c2cf97f75d009975f4d720d1fa6c19f4897
# 127     008451a05e1e7aa32c75119df950d405265e0904
# 6117    00078f66cd4321af437c7d9486bacb3b3b187328
# 16055   000055d41c8a62052dd426592e8a4a3342bf565d
# 946399  00000cb4a5d760de88fecb38e2f71b7bec52e834
# 6132845 00000055a78bf6735c4a89358fab1de34104c3cb

#
# code follows
# (you are not expected to understand it)
#

# this provides the "hexdigest" function we use later
require 'digest/sha1'

# this is the value we're checksumming/incrementing
# c.p. https://en.wikipedia.org/wiki/Cryptographic_nonce
nonce = 0

# this is the number of zeros we're looking for
# we start with a single zero, and once we find a
# matching checksum we will look for 2, 3, 4, etc.
zeros = 1

loop do
  # make a checksum from the nonce
  checksum = Digest::SHA1.hexdigest nonce.to_s

  # if the checksum starts with the right number of zeros...
  if checksum =~ /^0{1,#{zeros}}+/
    # ...print the checksum and the nonce...
    puts nonce.to_s + "\t" + checksum
    # ...and then increment the number of zeros we're looking for
    zeros += 1
  end
  # move on to the next nonce
  nonce += 1
end