Ruby as AWK

gistfile1.sh

# ruby -n option: Causes Ruby to assume the following loop around your script, which makes it iterate over file name 
# arguments somewhat like sed -n or awk.
#
# Example:

curl -s http://www.gutenberg.org/files/1080/1080.txt |
ruby -ne '
  BEGIN { $words = Hash.new(0) }

  $_.split(/[^a-zA-Z]+/).each { |word| $words[word.downcase] += 1 }

  END {
    $words.each { |word, i| printf "%3d %s\n", i, word }
  }
' |
sort -rn

# from http://tomayko.com/writings/awkward-ruby

and the -p option: Acts mostly same as -n switch, but print the value of variable $_ at the each end of the loop.
For example:

% echo matz | ruby -p -e '$_.tr! "a-z", "A-Z"'
MATZ

or

% echo matz | ruby -p -e '$_.upcase!'
MATZ