# double space a file $ ruby -pe 'puts' < file.txt # triple space a file $ ruby -pe '2.times {puts}' < file.txt # undo double-spacing (w/ and w/o whitespace in lines) $ ruby -lne 'BEGIN{$/="\n\n"}; puts $_' < file.txt $ ruby -ne 'BEGIN{$/="\n\n"}; puts $_.chomp' < file.txt $ ruby -e 'puts STDIN.readlines.to_s.gsub(/\n\n/, "\n")' < file.txt # number each line of a file (left justified). $ ruby -ne